As Dizzy Heights said, you do not want a penis that looks like a third leg. No human male can accomplish that size! It's all Photoshopped, so please stop dwelling over it. I'm being redundant here, because others have said it, but the average size is about 5.5, but that's to say some are a bit larger while others are less. There's nothing wrong with that, it's all who you are. If you feel pressured by tv, magazines and other girls/guys, then they're not worth it. You're you, you should be proud of your body. You'll reach puberty when it happens.

Also, as Shannon said, if you unexpectedly ejaculate or have gotten pubic hair, you're already beginning puberty.