I was thinking the same thing xD

How many messages did you send since her last reply?

It would help us analyze the situation if you text dump your chat logs here.

Girl? Boy? Why does it matter?

heheheheheheheheehehehehehe 

And pics of her.

Me: How was your day? 

*no reply*

Me: Hmmm, is there a chance I'm texting you too much?

Her: lol XD (WTF your texts were never this brief before)

Me: May I remind you, it's because you're awesome :P (We did say to eachother that we were both awesome not long before) 

*no reply*

Well this also happend to me once.. true story:
I also hit it of great with a girl around age 17... to good to be true so she got scared.. what if I was the one? what if she would spend the rest of her life with me? She got scared, ran of, married some other dude years later and had kids... Women tend to think about the future... and their options...

That's it??? WTF are you wasting our precious time for??!

No but her texts got way too brief recently, like "kl XD" and "ahahah LOL", should I text her again then?

Sounds like you might have been all talk no action as they call it.  Most girls like guys that are confident, but not cocky (don't confuse the two).  

You probably should have asked her if she wanted to get together to do something immediately like NikkoM said.    

I'm sorry if I'm sounding harsh, but it's kind of true.  I was really shy at your age and can understand, but the truth is that you won't get anywhere with the ladies if you aren't assertive.    

Sounds like she's occupied texting someone else, that she's more interested in, than you.

Your option now is to find out who he is and date him. That'll show her!