I'm going to reject having unprotected sex with my girlfriend, although I've done it before.
What does your girlfriend think about this?
Yes, she doesn't want to have any more babies.
It's a good idea to have protected sex, especially if you want to avoid having a baby.  Talk to your girlfriend to make sure that she is on the same page as you.
We have talked about it and she is alright.
It is good you are communicating with each other about this. Being on the same page in a relationship is important.