If you want to get checked fertility
(whether you will have baby or not) before marriage;you see these guidelines:-
1-are you getting proper menses
2-you can get ultrasound
of pelvis & reproductive organs done to see if all organs are normal in size & function.
3-on ultra sound
you can get done ovulation study to see if ovum is formed properly.
By doing these investigation you can find out if you can have baby;but still it is finally known only when you try to have a baby so till then we can't give any guaranteed answer for fertility.As for second part of your question it is not dangerous to have baby in your 30's but there are few problems if you wait more than 35yrs.