Best place

Any place you can hit off of local turf. You can get an online Titleist Ball Fitting consult, and they should recommend 2 balls. Then start with those 2 at the green side and work back to the tee.

I am a 2 handicap reaching 70 is there a difference in ball selection based on age?

Nope.

It is a factor of your current swing characteristics and ball flight and what your goal is. At 74 and now a low launch - low spin player, I prefer the feel of the Pro-V1 but need the higher flight and just that little more spin on approach shots, I stick with the X. At a 2 handicap, you can still focus on your launch window and short game results for ball selection without regard to age.

My ball loss is low, so I can stay with the X. If I lose more distance and/or balls, I can consider the TruFeel. Just not there yet.

A good fitter will have you hit 5-10 balls with the ProV1, then the ProV1X. Doesn't take them long to look at your trajectory/spin to give you great feedback. Same with the distance balls. For me, it's all about feel with the wedges.

Adding on to Ronnie's question here: Currently feel like I am better off the tee with the ProV1x, but better with pitching, chipping, and putting with the ProV1. What would you say is more important for the average golfer? I am an 8 handicap for reference.

If you watch any of the videos they have on ball fitting they always say it is best to fit the ball from green to tee. I