Maybe you need to change your thinking.
It was probably a good thing you didn't get married or have kids. If you had and you were getting high, it could have been an awful mess.
Now you have he chance to meet someone and have kids when your clean and sober. How exciting is that?
No way are you too old. I'm not sure if you are male or female. But I had a friend. She kicked heroin and had her first baby at 41 years old. Little baby girl, so gorgeous!.
Don't let negative thoughts come into your head. That's dangerous. For every negative try and a find a positive to it.
Take care
xx