Should i ask her?( girls ans please)?

so there is this girl i think likes me she does these things*** smiles lots when we both talk, touches me somtimes, teases me, she laughs lots but im told im very funny, ask if she could have lunch with me at school since her friends were away, looks at me from far away, and acually has intrest in what im saying by giving her honest opnion,we sometimes kind of lock gazess for a few seconds then look away a smile then look back. not sure if she does but let me no what you think. but i heard once she dates someone she ends up not likeing them because what she finds out about the person and then just stops talking to them. also she has 1 thing that i dont really like but it doesnt really bother me is that she uses drugs. when i say drugs i mean she said she smokes weed, does estacy, acid, she said she has tried oxy cotton and i dont do any of that and i never will do drugs. i just dont want to be involved with that(is that selfish) anyways she is really beautiful and i really like her and thou she does drugs i dont judged her because its her own life. also if we did date do you think i should ask her to stop doing the really bad ones like the oxy cotton and E and all that **** but says she can do the other stuff when she is not with me. also do you think i should risk it and ask her out i really dont want to mess this up but i dont really want get pressured into doing drugs with her. so please help i serously need it!!! ( note im 16 she is 15 and we are both in the same grade and go to the same highschool so we see each other daliy)