you are pretty young to be trying for two years-----NO JUDGEMENTS, I had my first child at 20yrs and he was born just 5 days after I turned 20. We have in many ways grown up together NOt always best. You are also terribly young to have trouble. If you want the advice of a mother who struggles constantly and I am married I have 4 children and I'm working on putting myself through school. I'm not a preacher. It's Flippin' hard. I would suggest that you put yourself into a better postion get through school first so that no matter what you can take care of that child. I hate to be a downer but if you have a baby today and in 3 years your childs father is in an accident can you afford to care for your child, your family. I wish that I had done that. That being said if you still want to go forth and keep trying I would talk to your obgyn and find out if there is scar tissue or anything blocking you from getting pregnant.
Good Luck
are you married and financially ready to start a family?