Here's my story

We were looking at wanting 2-2.5 yr gap. But because we needed help (metformin to establish cycles) with DS, we decided to start trying at 12 mths. I wasn't going to try earlier than that as I didn't want to affect breastfeeding in that first 12 months. Turns out I was super fertile after baby! We fell 2nd attempt. I had beautiful clockwork ovulatory cycles from 3 months post baby. So our first gap is closer than intended.. and closer still cos she was prem! LOL.

Again, cycles were beautiful 5mths post baby but the desire for #3 took a little longer.. and took a little twisting of DH's arm too So I think Kayla was 18+months old when we started TTC. And by that 18 months, my cycles were taking a turn for the worse and as you know were getting longer and longer and longer. All my fertility problems were returning and it took 16 mths to fall. So we have a 3 1/2 yr age gap. I must say, watching the age gap get longer and longer than what we wanted was hard Cos the other two were close in age, I didn't want the 3rd to be too distanced from the 2 of them. But you take what you can get really (and TBH we're enjoying the age gap )

So I guess from my experience, I would start TTC at the very minimum age gap you think you could cope with, and hope for the best I guess! In my case it's evident that my fertility is quite good after baby, and dwindles again over time (AF returned this time at 3 1/2 months). So I wouldn't want to be leaving it too long.

It's amazing how quickly the time goes tho hey. Our babies are nearly 6 months old already.. and if we were going for #4 i'd be wanting to start TTC again in only 6 months! LOL! Sadly... ain't gonna happen :/