In Feb this year, We had our very first fights on some issues like, I was jealous of her being friend of some other girl I didn't liked. We had some a huge fight because of that reason and some other issues like I wasn't able to go to a movie with and some friends and some more. Okay, I know that was my fault but later in April this year was her birthday I apologized to her by gifting her a book on 'The Beatles' and also a self made birthday card. We became friends again and on that same day I noticed her ignoring me and while I was trying to be friendly with her she just didn't seem to care. We fought again and this time it was real big. I haven't talked to her for half and year now. I really miss her and I got to know that she misses me too and that she asked a mutual friend about me so that friend told me later. I think and believe that we can still make it all right as its just half an year but the life's not over. We're just 15. I want to make it all right but I think that talking to her now would be really awkward and we have already ignored her for 1/2 year. She was like a sis. We had so much fun and all that craziness when we were friends,the secret codes and our secrets.
Do you think I can get her back? If yes, how?

You can attempt to get her back by treating her how a good friend should be treated. Jealousy and drama will never be attractive. But you need to realize at 15 you are still learning how to treat people properly. What you see in the reality shows you watch isn't real life. So do yourself a favor and live drama-free.

Go up to her and say hello. Tell her you miss your friendship and see where it goes from there.

If you cannot change your behavior for the better, then your apologies have no credibility if the same arguments keep happening, because of your jealousy, and insecurity, AND drama!