Reimu calls Suika a loli because she is still a child in an oni's lifespan terms. Suika is just some centuries old, and it will take millenia until she grows enough to look adult like Yuugi. The same occurs with other childlike youkai, like Satori or Cirno. This doesn't occur on Remilia and Flandre, because they are never going to grow up into adults becase they're vampires.
And now... Another chapter!
Did you remember to watch "Toradora!"? If not, too bad because this chapter may not look funny.
Another thing... Did someone guess which book Patchouli was reading on Chapter 13?
CHAPTER 16-Reimu Hakurei?! With the same kanji?!
-Not, not the same kanji, but the reading was the same. Thus, she really looked like you.
-Are you saying that you found another "me"?
-Kind of! However, she had purple hair and wore real Shrine Maiden clothes, unlike you.
-Well... I just don't wear a Shrine Maiden outfit because it's tradition in my family ( See Notes )... But... Purple hair? It's impossible. Every Hakurei has black hair, and you know that. That girl was a fake.
-That's the same thing she said when I told her about you!
-Intriguing! Tell me more...
-When she found me, she was like "OMFG!!! A KIRIN!! IMA SAVED!!!!" (See Notes), and I was like "Where I am?

", and then she was like "Help me! Shingyoku wants to test me, I need healing!!", and then I was like "WHATAHELL??"!
-WHAT? Did you mention... Shingyoku?! The Shrine's guardian?!
-Yeah! She was like "I'm the Shrine Maiden of the Hakurei Shrine!"!
-There was a Hakurei Shrine there?! But only two Shrines of Hakurei Clan exist: this one and the one in the Outside World!
-And then, I followed her. She had a fierce battle with Shingyoku, and that was my first glance at how bloody the battles in that place were. I mean, Shingyoku shooted Danmaku, but those were real deadly bullets! I could tell how deadly they were when I treated that Reimu's wounds. When the battle finished, I thought that everything would be fine, but Shingyoku just told that girl to go to Hell!
-Hell? That's nothing. I went there too, and there are just stupid pea-brained animals. Well, it's hot as hell ( BAD PUN AGAIN! ) there, but it was so only because that baka crow.
-The Hell there isn't the same. There were lots of terrible monsters, and the other Reimu could barely defeat them, because her ofudas didn't work on them, so she had to use a giant bouncing Ying-Yang Orb that could hurt them!
-A giant bouncing Ying-Yang Orb? That's ridiculous!
-She almost died many times, and I had to use the maximum of my healing spells to keep her alive. And then, she confronted something BIG!... AND OMINOUS! I'm still scared like a bunny because of that cursed thing. The other Reimu said that that thing was the Angel of Death, and that was her ultimate challenge. And I was like... "WTF!!! SHINGYOUKU WANTS HER TO DIE!!!"!
-Then?...
-I don't know how, but she managed to kill that monster. And I was like... "HOW DID SHE KILL AN ANGEL OF DEATH?!"!
-Looks like she was strong!
Rin took a sip of tea. She was shaking, as I could tell it by the way she was holding the cup.
-And then I, for the second time, thought that everything would be fine. And it looked that everything was really fine and peaceful... Meanwhile, I asked that Reimu to help me to get back to THIS Gensokyo, but she could do nothing about it... So I had to settle down. I thought that I would never come back...
-That was though, for sure.
-And there's something else that other Reimu has and is unlike you... She trained diligently, almost everyday.
-Now I'm even more sure that she's a fake. But... I think she really should train, since she lived in a land without SpellCard Rules.
-I was scared as hell to stay alone, so I always followed her on her trainings. One day, when we were returning from one day of training, the Shrine was overrun by a horde of youkais! And I was like... "REIMU!!! LET'S RUN FOR OUR LIVES!!!", but she just resorted to fight them all, confident because I could heal her... And then, she hopped over a giant flying turtle's back and took off.
-A flying turtle? Couldn't she fly on her own? Or she is just like Marisa, who needs that stinky broom to fly?
-It looked like she couldn't fly by herself.
-She is a fake. PERIOD!
-Anyways... She said we should investigate why all those youkais invaded the Shrine, so we departed on an BLOODY adventure! First, she beat the crap out of a girl that claimed to have created all those youkais, but she wasn't the mastermind... I felt very sorry for her, but the other Reimu insisted that I shouldn't heal the enemy. And then we entered a forest and a crazy bloodthrishty samurai girl tried to kill us... But after the battle, she just ran away like a chicken... And I was like "BWAHAHAHA!!! TAKE THAT, WACKO!!!", and the other Reimu was like "Just shut up and follow me".
-Hah, that phrase surely is like mine.
-And... And then... You won't believe this, but I found out we were in the Forest of Magic... So... Sooooo... We found an enemy I would NEVER EVER fight with!
-What was that?
-MARISA! It was Marisa!!
-WHAAAAT? A fake Marisa, too?! Now I wonder if you found a fake "you"!
-Well, surely that Marisa was a fake. She wore a purple gown, something that our everyday's Marisa would NEVER wear!
-YAY! You are talking about me ~ze! - Marisa appeared from nowhere and sat between me and Rin - Let's talk more about me ~ze!
-We aren't talking about you. Rin is telling me what happened when she fell in the Well of Anonymous'.
-Whatever. I still want to talk about me ~ze!
-Cut it out.
-I'm telling Reimu how I and a fake Reimu defeated a fake you.
-WAIT WAIT WAIT!!! What are you saying?! A fake Reimu and a fake me ~ze?
-Yeah. That fake you wore a purple gown and hat, and she didn't throw stars and Master Sparks at us. And more... She didn't say "~ze" after all sentence like an idiot, unlike you!
-How did that bitch dare to call herself Marisa Kirisame?! DID YOU KILL THAT IMPOSTER ~ZE?!
-Well... I'll continue the story. I warned the fake Reimu that I knew Marisa, but she didn't care and they battled like Kaguya and Mokou... And I was like "WWWAAAAHHHH!!! MY ONLY FRIENDS ARE KILLING EACH OTHER!!!", and the fake Marisa was like "You're just a ****ing weakling, you moron!!", and the fake Reimu was like "Shut up, stupid witch! GO POISON SNOW WHITE!"!
-And the fake me won!! YEAH ~ze! - Marisa didn't let Rin finish her bitching
-No... At the end, it looked like the fake Reimu won. She was like "Who's the weakling, you worthless wimp?!?!?!", and I was like "Let's make peace!", and the fake Marisa was like "You just got lucky! Mima will beat the crap out of you so much, SO MUCH, SO MUCH that you'll only see the grass' roots grow!!"... And then I was like "Who's Mima?", and then the giant flying turtle was like "The witch is right. Mima will kick your ass so hard that you'll pee through your mouth!", and then the fake Reimu was like "Shut up, you two!"!
-Who was that Mima? Was she the mastermind?
-Well, then I and the fake Reimu flew ahead and found an extremely badass-looking ghost woman, and she was like "I'll crush you so hard, SO HARD that you'll have soup made of your teeth!", and the fake Reimu was like "Shut up, greasy old hag!", and then I was "RAYMOO!! I can just heal, not revive!!", and then the fake Reimu was "Shut up, greasy stupid Kirin", and then Mima was like "I'll kill you, and then revive you just to kill you again!!!", and then they fought like Kaguya and Mokou, with a lot of Danmakus 666 DOOM FROM HELL OF EVIL FORCES OF EVIL, and then I was like "I'M GONNA DIE I'M GONNA DIE I'M GONNA DIE", and then!!!...
-Then?...
-And then the fake Reimu won! And then everyone was like "OOOOOOOOOOOOOOOHHHHH!!!!", and I was like "I'M NOT GONNA DIE I'M NOT GONNA DIE I'M NOT GONNA DIE", and fake Reimu was like "YEEEAAAHHHHH!!! I'M OVER NINE THOUSAAAAAAAAAAAND!!!!", and then we went home and there was no youkai.
And then Rin finally took a breath.
-Seriously, Rin. This looks like a story that would only come out from the twisted mind of a stupid and ugly drunkard from Outside World! ( See Notes )
-WAIT! There's more...
-MORE?!
(See Notes)
NOTES
Hakurei Clan's clothing tradition - As said in canon, Reimu's outfit is something like an "uniform" that every Hakurei must wear. See it in Reimu's profile in IaMP.
Random (See Notes) at the end of the chapter - Well, this "ground-breaking" narration of Rin is supposed to be funny. And, to make it look more funny, imagine Rin narrating all these things with the voice tone of Kushieda Minori ( from the anime/manga/light-novel Toradora! )
"Seriously, Rin. This looks like a story that would only come out from the twisted mind of a stupid and ugly drunkard from Outside World!" - ZUNZUNZUNZUNZUNZUNZUN