Yes, it is possible with certain kinds of exercise. The ones that cause you to burn up fat. Overdoing the jogging and the marathon running will cause small breasts, leathery skin, premature aging in the face of a lot of those cis-women I have observed over time. Some chest exercises may enhance the size of the breasts due to the elevation of the pectorals. You can exercise, but please take it easy.
Joelene.