Help! I need advice!

I'm 25 & my SO is 36. We have been TTC for a year now with no luck. I desperately want to be a mother. I have had some cycle issues, they're usually about 1 1/2- 2 weeks long and heavy. I have finally decided to visit my OBGYN and ask questions about whether I have fertility issues. Which terrifies me. I will see him on the 22nd. I have a few problems though. I'm not sure exactly what to ask, & my SO is concerned that we will not get any help because we are not married (we've been together 3 years, marriage is just not a priority for us). Will anyone give me some advice on what to ask.. and help relieve my anxiety? Thank you! & best wishes to all of you!