Postpartum Periods

My son is 4 1/2 months old and I’ve gotten three periods so far. The last two have been 25 and now 23 day cycle. My cycles used to be 25-27 days before I got pregnant. Is it typical for them to be this short? I’m concerned about being able to get pregnant in the future again. I’m due for my well woman exam and I’ll ask then but I want some peace of mind before hand or I’ll make a sooner appointment