I got married when I was 17 and pregnant and then gave birth to 4 daughters by the time I was 22 years old. That was  nearly 38  years ago and we're still together and happy.

My advise is get to know yourself first. Get into therapy and figure out your own issues because you'll be projecting all onto your partner and will think it is him.

We got into therapy when I was 27 and didn't quit until our issues were solved. Then we went back for check ups! 
I think when both people are open minded about owning their stuff and willing to say I need help or I am wrong it goes a long way to making the relationship work.