Mine is too short

[Pink Floyd]

I don't think that it affects your penis size, also there is nothing you can do about it now. There is an existent surgery, that digs more of your penis out. What surfaces (what you see when you pee, or ... other things) is only a small percent of your whole penis. There is even more under your skin.

And yes, it's perfectly normal. Everyone has a different penis length, that's just part of being a male human being. If you are capable of ejaculating, you will have no problems making a baby with your future wife.