What to do ?

Me and my boyfriend have been together since we were 16 . We planned on having kids later on in the future and build a family but things are starting to look dim . We've been trying since I was 18 after getting off ( Seasonale [birth control] ). For a while I considered it being birth control the case. It has been almost 2 years . I'm 20 going on 21 in August and still no kid 😞 I was wondering if something might be physically wrong with me or him because of our hard time of trying to conceive . I just want to know if you have had the same problem . What steps should I take ? What questions to ask my gynecologist? What can I do ? He's the only child and I would hate that I can't give his mother (father passed) or him a child .