I had two recurrent miscarriages one at age 17 and the other at age 18, is it possible to have a third miscarriage?

Yes possible: Yes it is possible. The main question will be to find out why you had two miscarriages before. Once you know the reasons-then hopefully you can prevent the future misscariage/s. Absolutely, it is important to tell your OB about previous miscarriages so certain things can be done to evaluate your risk. Certain condition-including clotting disorder can cause miscariages. Discuss with OB in detail.