Knowing if you can conceive

I'm only 20 years old and of course it is my dream to one day have a child of my own but not knowing if I am able to conceive is a fear of mine and I have been on and off birth control for the past year or so (switched from the pill to the shot) and I have recently decided that I do not want to take the shot anymore (only had one shot back in June of 2015) and ever since then I haven't had my period and I was wondering if that could cause any type of infertility. I'm just scared and getting my period is something I would rather have than taking birth control because it would give me the reassurance that my reproductive system is normal and healthy. If someone has any advice on what I can do to check that I can conceive please don't hesitate to give it! Thank you so much.