Realistic post baby weight loss goal..

For those of you who have had a baby already… How quickly were you able to lose weight when purposefully trying? I was just asked to be a bridesmaid in October, my son will be born in the beginning of July. The bride is very understanding and has no expectations for me pretty much aside from showing up on the wedding day. My only concern is looking like a whale 🐳. I started this pregnancy plus sized and would love to lose pregnancy weight and then some. So far I have kept my weight gain to about 15 pounds, going to try not to exceed that the rest of pregnancy. Is it possible to lose some significant weight within the first three months or so?