Will be boobs get smaller or perkier if I lose weight and tone up?

Depending on how much weight you plan to lose, you may find that the breasts will decrease in size and/or become more ptotic (sag); breasts generally do not become "perkier" with weight loss.   Best wishes as you reach your goals.

Loosing weight can influence the size and the shape of your breasts but it is unlikely to make them perkier. If you do loose a significant amount of weight and this is lost from the breast it will likely make your breast smaller and possible more ptotic. I would recommend a review with a plastic surgeon to provide you with further information. Good luck.Dr Guy Watts

It’s difficult to predict what the final results of
weight loss will be on your breasts, because each person carries his or her
weight in different parts of the body. Given that your goal is to lose
approximately one-fifth of your body weight, it’s unlikely that your breasts
will remain the same size, and you may lose some volume. Significant
fluctuations in weight can leave behind stretched skin, which can cause breasts
to droop instead of becoming perkier. However, at 17, your skin is young and
healthy, and it’s possible that any sagging is minimal. It’s also possible that
your breasts are still developing. I encourage you to pursue your weight loss
goal through a healthy diet and active lifestyle, and then see how you feel
about your breast size. Best of luck.