alright this is the best advice I can give. I am 19 and will be 20 in a few months. I started dating young, like 12ish or so, now while it has its upsides... one MAJOR downside is having to be driven everywhere, having mommy or daddy drive you and your date just plain sucks not gonna lie. At about your age like 14 and going into high school I decided to not date till I was able to drive the girl somewhere, worked out pretty good... I followed through with it and didn't date till I was 16 and a half. now I say 16 and a half because in CT you cannot drive with passengers other than your family for 6 months, so be careful and check your state too, nothing like getting pulled over on a first date haha. anyways it worked out great and I have been with the same girl ever since, so just about 3 years or so. I wouldn't say your too young, just give a little more thought into maybe waiting a tad longer to be able to drive from place to place thats all.
as far as not knowing if she likes you... you can look at it one of two ways, either ask her and possibly get turned down (which sucks, trust me, I know!) OR dont ask her and NEVER know what might have been. I asked out plenty of girls, sometimes I go the pity dates lol and sometimes, but I got turned down a few times too. If I was you I would defiantly go for it and if it doesn't work out or happen dont get down about it, and DON'T over think it either, you'll get down on yourself and it will hurt big time. Its a game of odds... if you only ask 3 girls out I will say you have a 1 in 3 chance of one of them saying yes... if you ask out 30 I will say about 10 or so will say yes.... so one date/girlfriend or 10? lol I mean its your call just saying.
also when you "ask her out" don't just ask her to be your girlfriend... that's lame, ask her to actually to go do something, I personally wouldn't make a first date a group date... but that's just me.
This is just my advice from my personal experiences, so if it doesn't work out, I am not responsible. HOWEVER if you follow my advice and it does work out... you owe me! haha
Best of luck to ya man!
-Collin