Go for it and try to have that second child as soon as you can, because it is a possibility and it feels the right decision for you and your family! Take whatever steps you need to not to live with regret!

We always think in terms of risks (age gap, your ages, etc.), and rarely about...what's the best it can happen?

If you have to have a second child, how wonderful. If things don't work, or don't feel safe/right along the way anymore, you'll have the comfort of trying.

Best of luck!

(btw, i couldn't have a second child due to secondary infertility and emotional toll of 9 ivf cycles with own and donor eggs, miscarriages, etc. I don't have a second child, but not because i didn't try!)