My friend was married to a man who was 24 yrs older than her, but she was 23 yrs old when they got married. They were together 24 yrs before he passed away from cancer. A person changes so much between the ages of 17 and 23. Your hopes, dreams, ideas all change. If you do want to marry this person, I would suggest you wait until you are at least 23 yrs old before you do it. If he has children, they are probably your age or almost your age. And that can cause problems.