You’re in college at a young age, starting before most do. So he probably used the “You’re mature for your age” line and while that is true for you, it’s not the same for him. 19 year olds don’t go out with 15 year olds for a reason. First being that it’s illegal and secondly there is a large difference. Even though four years may not seem big, it is right now. You have your whole life ahead of you and a great head start, take advantage of it. Finish college, get a job and probably sell the house so that way you’re not using the inheritance to keep it as you’ll be paying property taxes on it. Once you’ve done that really think about if you want to stay with a guy who went after a teenage girl as opposed to someone closer to his own age.