When I was about that age my Dad bought me a weatherby vangard VGL in 243 and I still have it and up until about 5 years ago, I still used it.. The only reason I retired it was because my Dad passed on and left me his Model 7 in 243.. So now I shoot it and the weatherby is on idle until my son is old enough to shoot it.. The 243 is plenty for any whitetail around.. If your unsure about the smaller bullet, just go up to the 7nn-08.. It is a necked up 243 from 24 caliber to 28 caliber, use the 120 grain bullets and there won't be much difference in the recoil.. I have a 7mm-08 in the ruger compact that I love..