Im 19 years old, i eat healthy and exercise but my breast size never seems to increase, is there something else i can do to change that?

Breast size: Breast tissue is primarily glandular & fibrous tissue, not muscle; the pectoralis muscles lie beneath the breasts. So eating healthy & exercising may enlarge the pec muscles but not the breasts. Obese women may have larger breasts due to added adipose tissue. If u are dissatisfied with your breasts, consult a plastic surgeon about possible augmentation.

Breast augmentation.: Once breast growth stops at age 19 or 20 (rarely older than that), your breast size depends on your hormone levels and weight. Pregnancy and lactation hormones will make breasts temporarily larger, but there is not much else you can do other than pursue breast enlargement with implants. Some surgeons use fat grafts, but the long-term safety of that procedure is not known.