I would speak with your doctor about the Hormones you are on .
It can take up to 5 years even longer for some woman to develop their breast . They will seem like they are growing fast and then you hit a stand still ,which if feels like no growth at all . Your breast size will be based on your genes and other factors , your height , body weight etc ..etc … just like it is with cis-gender woman . Like Michelle said , not sure where you are on your transition , but yes , speak with your doctor if you have concerns .