Bedroom troubles

Okay so ive always been into girls but i never really acted upon it out of fear. I just recently got into a relationship with a girl around 2 months ago and ive tried going down on her twice but i feel like im not doing things properly. She hasnt orgasmed and its making me really insecure. Ive never done anything besides finger another girl and i dont masterbate because i dont get as excited like when somebody else touches me so im really lost on what im doing wrong with her. She keeps brushing it off and everything saying sex doesnt matter but its really bothering me. Any tips or suggestions?! Please!