I'd get it shooting about 1" high at 100 yards. That should cover you for as far as you can reasonably see with your 62 yr old eyes.

You might surprise yourself with your accuracy if the gun wears decent irons.

Spend some time at the range and you just might find you can shoot 150 yards with those irons. Course, you could always get it scoped and then I think you'd find yourself being hard pressed to NOT take a 175 yrd shot on a nice buck!