How do I get my boyfriend back?

This is my first breakup/heartbreak. I am completely clueless on what to do. Everyone tells me I just need to move on and forget about him.. But I can't. I'm only 16 years old.. but he is really the one I want. I know there's "other fish in the sea". I've talked to him a couple times, asking him to give us a second chance. But he won't.. He does but he doesn't. He says he wants to be on his own for awhile and doesn't want to date until after high school. I respect his decision, and of course I want him to be a confident man. But I don't want to lose him, he's my best friend and the only person I can talk to about anything. I have friends and family.. but it's not the same talking to them. I've practically begged him to take me back.. (which I don't think was a good idea..) I wrote him a letter telling him how much I truly love him and how sorry I am for being how I was. He told me that he's gonna keep reading the letter and hopes he changes his mind. I know he loves me.. But what can I do to get him back? I don't know how to live with myself right now. I seem so dependent but I don't want to be. Should I give him space? Should I talk to him about it more? What should I do? This hurts to much and I miss him..