First off, James, I'd like to say sorry for what happened, it seemed like you both shared a great relationship.
But as you asked you need some help

What you thought was the problem that probably pushed the break-up into effect, was texting her when she asked for space.
Making her think of you brings back many and any kind of memories maybe ones she didn't like.
you shouldve gave her space, texting constantly shouldve been a NO-GO. Texting or talking to her once in awhile seeing how she is, and telling her you're giving full support for what happened wouldve been a good choice
Maybe thats what pushed her from what you did.
And before, you shouldve never got drunk if your with a girl you care about who is a non drinker, especially if you get like that. But don't let this put you down!
Okay now for the prime advicee
Do not apologize if only you apologized alot before when after the incident happened, she might get tired of another sorry speech.
What you should do is say how you changed and will change for her.
Her texting you every now and then, show that she still wants you there in her life, maybe as a friend or maybe she just wants you to say something important that will show you changed your ways for her and you want her back. Also, you being her first, can help alot for getting back, I know alot of girls who wanted their firsts back alot. Because they will always remember and maybe cherish that special moment of their lives. They feel Very comfortable and happy with the person they are truely intimate with in a relationship
So, do what ever you said you did at the bottom of your text, but when you do, make sure you bring the conversation to those things i pointed out for you.
But YOU MUST know thyself. If You REALLY want to get back with her and feeel that it should happen DO IT, but if you feel she dosen't want you back, or you just don't think things will be better if you are together again, DONT DO THIS, follow Alex's advice on how to move on, maybe when his new E-Book comes out (i wonder when that will come out, and I hope us members get it for free lol) will help.
OTHER JKTC Members, I don't know if this advice is great soo help me and James Out hereeee!!