No it’s not wrong, your boyfriend is entitled to his opinion but you did it for you not for anyone else ! It’s good that you have taken his remarks with a pinch of salt and that you know he isn’t being mean saying it to you.
From what I gather from the ladies in this forum it takes sometimes months for your boobs to drop properly and look more natural, you never know in a few month time your boyfriend may just turn around and say it was the best thing you ever did.
I hope that you love them and don’t worry your boyfriend will learn to love them x x