At what age does the bobs stop growing? why does my breast look like little kid still if am 23 years old already? when are they going to change?

Probably no change: At 23, it is most likely that you have completed breast development. Breasts come in all shapes and sizes, even if popular culture would try to have you believe that one size is better than another.

1. They can...: ...Grow at any age; typically, they have a "growth spurt" with pregnancy; 2. If you have normal periods, the breasts are probably "fully functional" as they are; 3. See (1).