Need Info for asking a girl out??15 yr age?

Ok. SO im 15 (guy) and i just started to chat with this girlat my Retreat for church like last saturday 20 or 19th of this month and so i was talking to her and stuff making her laught etc. but at the last day sunday 21th we were coming back from sierra vista to OMOS and i was talking to her making her fell good happyand i said Ur cute etc. she said she likes me and that im sweet and a loveable person and i asked her out and she said i have a boyfriend and she told me her boyfriend lives in New MExico and i said thats long term it doesnt last verylong u know? and she says i know jsutbut.. and i interuppted saying well is he from back then , she says well yeah , idk what to do i REALLY like or love her and idk what to do ?? make her convince her to break up with current to be with me or just be patient or how do i do this PLZ HELP??