My girl is worried that I'm too damaged from my childhood to have kids with me?

I don't know why your girlfriend would say that unless she has personally saw signs that you might be abusive such as you having a bad temper or other signs?? I'm not judging, but there could be more to the story than you have revealed. I urge you to get in counseling and maybe your girlfriend can go with you to some of the sessions so she can see that you wouldn't hurt your future children with her, should you choose to have them with her.