You'll continue to have breast changes for as long as you menstruate, basically. That's why a woman who has trouble breastfeeding a child shouldn't necessarily throw in the towel for all future children - you keep creating more breast tissue. However, these changes won't necessarily allow for a significant cup-size change. It's not impossible though
If, after this growth spurt (or whatever it is) ends, you're still not quite where you'd like to be, remember that pregnancy is the next best thing to puberty for naturally expanding bust size. The women in your family might have been smaller pre-partum. You might ask them about it?