How long should I try getting pregnant before calling my doctors?

6-12 months. This depends on how old you are to start with. If you are < 35 years old and healthy you should wait a year before getting too worried. If you are >35 years old or have medical problems or have had problems getting pregnant before, you should see your doctor after 6 months of trying.
At your age. If you are ovulating 6 months at the most, if you are not ovulating then right away.