Why do chicks that are your best friends flirt with you?

I mean like I wore this suit today and shes never reacted like this. I mean she was like making fun of me, but in a fun way kind of. And you could tell she liked how I looked. But I don't know if that means she has feelings for me now or what. I've known her for about 4 months and we haven't gone out or anything yet. And whats the best way to ask her to homecoming without making it akward for both us?Why do chicks that are your best friends flirt with you?
Your best friend was flirting with you because she thought you just looked cute in the suit. :) Some girls flirt with guys they don't even like, but an effort to try to get closer to the guy. Best way to find out if she likes you is ask her or notice the hints she's giving out (like eye contact, staring and/or smiling a lot, laughing a lot, flirting a lot, etc.). Also, if you're going to ask her to homecoming, try to be prepared on asking. If you are too shy to ask it in real life, text her or give her a note during class. Hope I helped. :DWhy do chicks that are your best friends flirt with you?
I was hoping you would like this suit as it is what I plan on wearing when I pick you up for HC.