I have 17 and the same body since I was 12 years old?

I'm not a developed girl, I've had my body since I was 12 years old, menstruating, but my period is not normal. What to do? Help me, I'm 17 years old and I'm very thin, without body and my family is not that thin; Should I take hormone?
Expert answer:

Should you start looking for a doctor, only a medical evaluation is that we can know what should be done specifically in your case.