RE: 30-06 or 7mm Mag
It depends on what you are hunting. Their both an excellent callibre in my mind. For deer size game both will work equally well in their own ways. With the 7mm you get a lighter bullet with alot of powder behind it that is very flat shooting and good for longer ranges. A 30-06 gives you the option of choosing heavier bullets but it isn't quite as flat shooting. Both calibers hit hard. I use the .30-06 for all my hunting needs and it has preformed well in many situations. As far as for you im not sure you would have to handle both and maybe even shoot them to see what feels best. Both calibers are on the larger side for someone your age unless you dont mind recoil. When i was your age i hunted with a .270 it is a fine caliber that you might want to consider as well. Its hard to say which one would be better for you if your shots are going to be anywhere from 1-250 yards the 30-06 will do the trick.
Remember deer aren;t that hard to drop so you should look at something that fits you rather than something thats big and powerfull and is just going to develop bad habits.
hope that helps buddy!