Enjoy your first teenage year- It goes by like a flash, seriously.
If I were to give you some advice, I'd say don't get too cut up about the fact that you don't have a girlfriend. And if you do, seriously, what?
You're 13, go do stuff with your friends. You're not going to be 'going out' with any girls. At least not in any serious and emotionally satisfying way.
But yeah, biggest advice I'd like to give you is that you're only young once. I'm not burned out past my prime, ha ha, I'm 14, but seriously, you're only getting older.