All my snakes seem to grow at different rates, I tend to feed my females the biggest adult mice since I want them to grow big to lay eggs. I raise my own rodents so I have a lot of different sizes, I'm still wishing I had more large adults for everyone. My rats just bred for the first time so pretty soon I'll have enough!
just keep feeding every week, I'd probably move up to bigger mice or one more if I were you.