I waited until I had kids and so glad I did. I have assymetery anyway but my larger breast grew and my smaller one didn’t at all and they stayed that way even after I’d stopped breastfeeding. If I’d have had a BA before kids, I would’ve definitely had to have another one.
One of my friends had a BA 12 months before she fell pregnant and she wants to have hers done again, but then I’ve got a friend who’s had 2 kids and her breasts are as good as new!
Everyone reacts differently to pregnancy so it really is your decision.