When do you know it’s the right time to have a baby?

I’m 26, engaged, work part time, have a mortgage..I have most of the things you’d consider when having a baby but when do you know it’s the right time?

Part of me wants to enjoy more time with my partner just us, I want to get married still, travel a bit more, get a better job. I’ve said for a while I wanted to wait till I was like 30 but I have times (like now) where I can’t help but think what if?

I worry about fertility and I just keep thinking how much I want children idk, I guess I just wondered if anyone had any idea of when they knew they were ready?