I like a with a man with a child...

I’m 23 and he’s 30. He has an 11 year old son. He and I have been hanging out. He was very honest with me about his son from day 1, and I didn’t think much of it. But now that we’re really starting to fall for each other, I realize that I’m not ready to be a mom. I want to be a mom eventually, but I’m way too selfish right now. The sons mom is actively involved in his life, so I wouldn’t really be the mom, but I can’t handle even being a step mom right now. Especially to a middle schooler, but I REALLY like his dad. Any advice?

Edit: while I’ve never met his child, I know I would love his child. I just don’t know if it’s fair to try to be a step parent to this kid if I know I’m not ready. And I don’t know whether to compromise or if that makes me a terrible person.