Im going crazy

I'm 18 years old and me and my boyfriend have been together for almost 2 years we have jobs and we are doing very well on our own so we decided we wanted to start trying to have a baby well .. that was a year ago we stopped using condoms and haven't used one since I have irregular periods they some times seem to have a pattern and sometimes they just don't come that month I'm scared that a doctor won't take me seriously because of my age.. so I don't know what to do if any one could give me any advice that would be great!! No rude comments please!