What should i do please help :(?

this is a long one so please bare with me : well abou 2months ago i met this girl in my honors science cl named sarah we had gotten seats next to eachother and she talks to me alot soon we became good friends she always tells jokes to me and we make eachother laugh and when i was sick she was concered for me. Also i even took the blame for her when she broke a beaker in science cl.Now everything was good until we had a school embly in the auditorium she was really happy i got to sit next to her then my "friend" jacob goes off and be a jerk and says to her hey sarah stop flirting with dan he's already taken she got sooo pissed of at him and now she doesnt talk to me as much :( should i ask her out or are we just friends!??!