Is it still possible to salvage a past relationship... to restablish a connection with an ex-girlfriend?

Excuse me , sir or m’am. I would like you to understand that I am only 17 years of age, but I would like to take a particular relationship seriously. I know I’m just a child, I just thought coming here would bring me the guideance, I’ve been longing for. I’ve really put myself in a bad situation. As my ex started calling me often, I lost my temper one day, and used foul language. I let everything go for awhile, and decided I’d contact her again to apoligise. I read her an apology letter over the phone, and tried to be sincere. She said, she forgave me, but decided we’d just be friends. She originally did like me more than a friend, but now she says I’m just a good friend. I would like to accept that, but I’m too stubborn to let one of the first girls that actually liked me go. She still calls me occasionally, like when she’s at her new boyfriends house. It’s all so strange, she said she broke up with this boy because he cheated on her. But when I make a false move, she came right back to ‘em. I’ve been trying to get her to express personal feelings again, while expressing my own, but she just says I don’t know. Hell, I just try asking her if she even likes talking to me, her response is SURE. I’m just trying to make things right, fix what I have broken, and get back on track. I understand the basic requirements in a relationship: care, understanding, be sincere, be faithful, to comfort your partner, and just be there for her when she needs help. I’m really uptight about things, I’m really sorry. I dont want to disturb and pressure her, but I also want her by my side. I dont think she even wants to hang with me anymore. For about 5 days, when she didn’t contact me, she just said she was busy and her old boyfriend was responding to some of her texts. As of right now, she still calls to say what’s up and I guess make small-talk, here and there, but like I said, I don’t think it’s going anywhere, and I don’t know if I should just wait for her to contact me or wait to get back with her, if it's even possible. I suppose I managed to work it out with him, but she said that when I do try and contact, and when she wants to talk, she’ll say she’ll try and keep her phone away from him. Like I said I’m really sorry about all this, I just want some help fixing this. Insight, opinion, and advice would be appreciated. (The girl is sixteen by the way) I just want some hope to salvage the relationship and restablish a connection with her. I've tryed getting help from family and friends, but reguardless of this 'puppy-love", everyone just tells me to move on, but I dont like leaving a relationshop broken. It's not right. She called me today and we talked for a few minutes, but she also said she would call tonight if she didnt forget, but she never did. Like I said, advice would make me grateful. And I'm worried she might never call again. I always thought a woman would know best. I know it all sounds crazy, but as much as I'd like to contact her, I don't much because Im afraid to, especially being she went back to her ex right away and goes to his and his friends house alot. (she usually tells me she's over there or going there ) The only other details I can give is that she says I'm a good friend, she only likes me as that, she claims he loves her, nevertheless of the claim that he was unfaithful, thus, she broke up with him and was always nice to her, and when I was with her, she said she didn't like him anymore, but they still communicated and were friends. Like I said I'm really sorry about everything, I just feel so broken and used. Each relationship role here was basically shifted. It just makes me feel sick knowing she's so happy with him and spends so much time with him. I'm not a stalker, I just care too much :(