I have recently upgraded from my 07 Avalanche to a 2013. With my old truck I could program the keys and the fob myself. I have been told on the 2013 I have to take it to the dealership or a lock smith. But there has to be a way to do it myself. Any advice would be appreciated. Or do I have to take it to the dealership?

You do. I can't remember the year they transitioned, but they did. I think it was late 200x'*.

2010 and up have to have the dealer, or a locksmith unfortunately.