You don't need to be so quick to label yourself. It really doesn't matter how long it takes you to figure out your sexuality, it's just important that you get it right. If you only think you're gay because you enjoy looking at gay porn then chances are you're really not and are just simply bi-curious, as most people are at some point during their teenage years.
Also, it's normal to be jealous of other guys, almost everyone experiences jealousy/envy of other people all the time so it's nothing to worry about, and if you think you're straight but don't want to get back into the whole jealousy thing, then don't worry about it, everyone feels jealous, you're human.