Wow it does sound like a lot of things happened in here. You definitely do not want to pressure someone into "decide right now" - giving them time to think is always the best option. Giving them space is also important. You've pressured her a number of times now and she is really upset by it.
You need to prove to her - through your words and deeds - that you have learned from all of this. People make mistakes as they learn and grow, we all do. It is part of life. So yes you made mistakes, but you've learned from them. I'm sure she's made mistakes in her life and has learned from them.
So give her a few days and then *send her a letter*. Letters are good because they can be read without pressure and thought about. Explain to her again that yes you made mistakes, and that you realize them, and acknowledge them. Then lay out exactly how you plan to be different going forward. Don't just say "Oh I'm better now!" Be concrete. Show her that you have learned from this.
Don't ask her to be dedicated bf/gf right now. That would be a huge leap. Instead, JUST ask to be able to see her for drinks / dinner sometime in the future, to be friends. Start very low key.
