If you're having regular cycles it's unlikely breastfeeding will affect your fertility - if it did, you wouldn't be ovulating regularly.
It's a tricky one, truly. If you weaned and fell pregnant right away, you'd probably feel ok about it. But if you didn't, you may well end up feeling regret about it.
Have you spoken to the ABA? They might have some resources on this, which could help you in making your decision.
All the best & good luck ttc - hope it happens for you soon and you're able to breastfeed as long as you feel is right.