I screwed up...

🍄🦄Fawn🍀ஃபான் • Member of the Cherokee nation. Cocker spaniel enthusiast. Witch.
Oh god.. I'm so ready to offer advice but here I can't trust my own...
About six months ago I was asked out by this amazing girl. She was absolutely my entire world. However there was some family drama that took over my entire life. I pushed her away and we ended up breaking up. 
I was in a very bad place emotionally. I was in a lot of pain and was using guys to try make it all stop, and I never quite let her go... We remained close friends thoughout even though I hurt her very badly. 
Then, about three or four weeks ago, I finally got myself back into a good place, and realized that I wanted her back. We ended up almost sleeping together and the next day I asked her out. 
I joke around a lot, and I think she thought I was joking so she wouldn't say yes. However, I have made it clear that I want her back and she's said she just can't right now. 
I'm pretty sure this is because she's scared and I just want opinions... Do I get on my knees and beg, show her I'm completely there and support her no matter what, or just back off?
Im sorry I know this is dumb high school drama I just need some advice.. 
Thanks in advance! ❤️