Well do you have those messages that show the person say they're 19? IF you do, then it would be the parent's fault for letting their kid misrepresent themself on the internet. I think this was probably a prank or a snooping parent trying to scare off all their kid's friends. This can happen whenever you are on the internet doing this type of thing. In the future make sure only have sex with people you know are over 18 (know them personally or have seen ID). I really don't think you can get in trouble for what you already did, and why would the parent of a 17 year old even persue something so ridiculous anyways? Their kid is almost a legal adult. If that person sent you pictures of themself, it is child porn so that is illegal, so make sure you only use adult websites and not free ones like MySpace where people can just make stuff up.