Seems a lot of folks aren't aware that tires dry rot. I don't drive a lot & usually have to get new tires because of dry rot way before the tread is gone.
you'll be fine with that. might actually get a little better mileage. age tends to be factor on how you use vehicles. I'm 70. resale? I doubt it to be a resale issue. Does anyone ever look at or consider gear ratio to be a deal breaker on a used vehicle?