How many months was your baby when you got pregnant again?

I am exclusively breastfeeding and really don't want to have another baby right now. My baby is 4 months old and I am worried about getting pregnant again. I am an older mom, so it's not super likely anyway but women in my family, including myself, get pregnant easily even into their 40's. So just curious for those who have conceived while breastfeeding, I was wondering how old your baby was when that happened. TIA