A couple thing to consider...
1. The cost of buying a .308 AR or bolt action rifle will only go up as time passes.
2. Life has a way of taking hard right and left hand turns, for the good and for the bad.
3. Laws change, what is available now my not be available tomorrow or in a year.
If you have the money now I'd buy a .308 rifle now. you can sell/trade it later if you find you don't use it or loose interest. Your current life situation can change, where all of a sudden you have more time, live closer to an outdoor range, etc. Laws can change where you find it becomes very hard to buy a larger caliber rifle.
My thoughts...