Lots of guys your age are into hentai and tentacle porn - that's nothing to worry about. Lolicon can get you arrested in some places, though. I'm not sure what "underage" means in this context. Attraction to prepubescent children is a serious problem. If it just means after puberty but under the age of consent, that's still ILLEGAL in some places, but considering your own age, it wouldn't be abnormal for you to be interested in it. Just don't. Think of the consequences.