I am 16 years old, my last period was in september, is their a risk in waiting a while to get checked up ? i believe i have secondary amenorrhea

Evaluating risk....: I imagine that it's not easy to see a doctor - but it is probably best to do it sooner than later. Many reasons are not life-threatening, but a few involve fairly serious issues like thyroid and even glandular tumors. Treating whatever it is can be a good thing. If it's $, be frank and many Dr's will work out a pymt plan. You're worth taking care of!