If I may be a third party trying to butt into the conversation -
@boag, from my standpoint (and only reading the last few posts), it appears that you're the one who's preventing the argument from being possibly constructive.
My view of the argument is that CyanHide appears to be taking issue with your definition of "thirty years old", and is asking you why you think the subject is thirty years old (quote: "Does the fact that he has his memories of a past life intact make him older? Would it be fine if he had no memories, like traditional interpretations of reincarnation?"), yet you appear to be completely avoiding that line of thought by insisting that sex between a thirty-year-old and a fifteen-year-old is inappropriate. This is holding up the conversation from a natural progression. You should probably be responding by starting with why you think MC is thirty years old, even if the reason seems obvious to you.
If you do think that, for example, the fact the MC lived to adulthood in a previous life or has memories of living to adulthood makes the current him a bona fide thirty-year-old, and say so, then we can probably end the argument right there as a difference in opinion and both of you can respect that difference in opinion.
@CyanHide - If what set you off was his comment "so you see nothing wrong with a 30+ Yo Dude engaging in sexual activities with a 15Yo? ill say it again, have you stated this to your family?", I don't think that was intended to imply that you and your family were in support of pedophilia. It looks like he was asking from the assumption that your family, if asked such a question, would react badly. That he used the word "stated" instead of "asked" seems to indicate he believes you already "see nothing wrong with a 30+ Yo Dude engaging in sexual activities with a 15Yo", though, but it's possible that that was just a bad word choice, given the way he was trying to attack the assumption.