Nervous

My boyfriend and I of 2 years have been trying for a child. I am 19 and he is 22 and already has a daughter from a previous relationship. I am going to make an appointment with my gyno because I want to know if I am able to have children. I am just unsure how to go about it because I am so young but I have been trying to conceive for a year and six months now and I get my period every other month. Do you ladies have any advice on how I should ask or come about it?? I feel nervous to even ask. Help please