Should i ask this girl to prom?

Shes a sophmore im junior but iv never reall talked to sept once but i know shed be vibin me cuz i see her lookin at me somtimes snd i mran i sure aint ugly but im just saying... I first planned to go solo so i could dance with all the girls but they all taken now from what im guessin so i thought id ask this chick. Uhh she doesnt know any of my friends so would that matter when were in the limo or after party well have? I think not but also well probably sleep over a friends house ill ask her if she wants to but i dont what to expect as an answer or what shell wanna be doin later? Alllssooo how should i ask her, member i never talked to her, i even think she may have a Bf but from another town so who givess.. And she i ask her alone cuz itll be hard to find her alone? Thanks sorry for t bein long but say somthin if u got a tip cuz i may of left somthin out