Advice on talking to your partner about your stance on children?

I’m 27 and my Fiance is 35. I was 23 and him 32 when we got to together. At the time, I felt too broken to ever be a mother but now I feel different. I had wanted children when I was a teen but changed my mind in my early 20’s due to my mental health. So when I met my bf I was in the “do not want kids” dating field.

I have been getting better mentally and I feel like now I would truly regret not having kids.

Tbh I feel like if he wanted a woman who knew 100% what she wanted in her life, he should have chosen one close to his own age with a fully developed prefrontal lobe. It’s probably best we cross this bridge before we actually get married but I’m scared of ruining my whole life. He played such a big role in why I even feel safe to have children but I’m afraid he’s too set in his ways to change his mind. 😞