First of all let me start by saying, your site is amazing. Your answers remain as biblical as possible and I do appreciate that. I read in another question someone else had that was very similar to the situation I am going through now, and reading your response really helped shed light.
Nonetheless, I recently "fell in love" with this girl, who is underage. I am 24 and she is 17. When I think of what I have done, I feel completely disgusted and ashamed of myself, and guilty. We had sex. After we did, the next day I wanted to speak to her to end things because we both wanted to have a relationship that honors God, and we tried but failed on every level.
I definitely learned a huge lesson. I am not ready for a relationship anytime soon, and I should only be focusing on God. I decided to end things with her because I saw how bad my relationship with God was suffering, and us being on two different spiritual maturity levels was wrong enough. I have been Christian for two years now, and she recently accepted Christ. I was foolish to think something like this could have worked out.
Nonetheless the problem now is, even though we have ended it and gone our separate ways, I feel terrible because I technically broke the law by having sex with a minor. I know true repentance leads to action, and I have let her go. I still feel in my heart that I want to speak to her once more to apologize for treating a daughter of Christ with no respect or regard. I am ashamed. Is it biblical for one to turn themselves in to the police for something like this?
Please, I need help.
I'm more interested in the law of Christ than than the laws of man. Not knowing where you live, I can't verify this, but in most places the laws forbidding sex with a minor (sometimes referred to as statutory rape because it is argued that a minor cannot give consent to sex), applies to someone 16 or under. My guess is that you had not broke a law of man.
However, that is certainly not true in regards to the laws of Christ. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4). You committed fornication, which would remain true regardless of her age.
While you saw this relationship as love, it is apparent that it was more about physical attraction than interest in someone you wanted to marry. I don't know how long you two were dating, but I would not be at all surprised to hear that it was relatively short. I know you see yourself as the aggressor in this sin, or at least the one who should have known better, and the later is true. What I can't determine is why the situation got out of hand.
I can't say whether contacting her after what you did would be best or not since I don't know the motivations of the two of you. I suspect that she would view the situation as being used by you. After all, you broke up with her right after you had sex with her. I understand your motivation to end the sin, but I don't know if you got that point across to her or not.
The saddest aspect of this situation is that you sinned with a new Christian. Where you should have been an example of purity to her, you led her astray. I'm glad you have repented of your part in this sin because God takes a very dim view of this sort of thing. "But whoever causes one of these little ones who believe in Me to sin, it would be better for him if a millstone were hung around his neck, and he were drowned in the depth of the sea. Woe to the world because of offenses! For offenses must come, but woe to that man by whom the offense comes!" (Matthew 18:6-7). Technically you were not at two different levels of spiritual maturity -- you both acted immaturely.