It definitely just depends on your body. I breastfed my daughter for 20 months and my breast shrunk a little after I stopped. But not saggy. I think age may be a factor due to elasticity.
Ur boobs dont always get saggy from breastfeeding. I have breastfed 2 children . Size D and never had saggy boobs
Every woman is different. If you breastfeed then, of course your breasts will get bigger because they will be producing milk. I was a B cup before I had my daughter and they didn't get bigger while I was pregnant. I nursed my daughter for 16 months and I was a C cup. When I weaned her my breasts went back to their original size and shape. They aren't saggy either, I always say that someone would never know they fed someone for a year and a half.
They are hard a full because they are full of milk. They'll eventually go back to normal
If you breastfeed they will get a bit seggy , after u give birth they will get fuller and hard but after you bf they get to the size again until they fill up with milk again, i breast feed for 2yr so mine whent seggy i dont know if you dont bf what will heppen