I promise you that hot girls (especially), don't invite unwanted advances on themselves. 110% percent follow your heart, ask her out on a proper date~ and don't leave her hanging by being emotionally withholding. I can guarantee that she was nervous about potentially ruining your relationship with an unwanted kiss... and I promise you should let her know that you liked it very much.
This is the type of emotional maturity that makes women, especially at that age, dig slightly older guys, and if it was me, what i'd say would outline into a few points:
you obviously know that I love your company, your sense of humor, (embellish, etc.) right? you make me happy. and, I think you are beautiful. you are beautiful.
I know sometimes I can be shy to a fault, and hopefully my shyness didnt interfere with our kiss. If it did, I think I need to restore my family honor by kissing you again,,, perhaps... like right now.
am I allowed to ask you out on a date ? I honestly didn't know if you were teasing me with your premier 1-liner skillz, but I liked it. and hopefully I could start recording them into a semi-autobiographical screen play I've been writing about being the king of B-movies.
then ask her out. pick her up, or get a lyft if you want to drink/go somewhere. make a dinner reservation. let her know that you trust her, and applaud her bravery.
if she was just fucking with you, tell her that it woke something in you, and for the sake of science, could we have just 1 or 3 more kisses?
good luck op.
source: former shy guy, former fat guy, former cynic :) pm if you want, I guarantee you she's into it- if she says she doesnt want to risk your friendship, tell her you've felt this way for a while, and everything is so far so good, and we can go slow.