|The younger you are, the more change there will be, however, augmentation for over 21s? not really... I started at 19-20, and I hit 36C naturally.... upto 30 there can still be suprising results, after that it does happen to tail off somewhat. upto 24, human growth hormones are still at 'growth; levels, so you're pretty safe.
Shapewise, your body will collect fat in new areas, so work out and keep fit, and your figure should stay good, or get better... running is a good overall cardio to use really.
At a younger age overall, the effects should be more similar to that of normal puberty, you will bud and grow, bone structure will be effected as you're still developing, and you will develop as any other teenage girl. Not a bad lot really.