(which you are) mostly when they live in the back and beyond of a reservation and wouldn't be able to do the frequent follow up visits at one of the clinics there. The valves can last up to 10 years but rarely more than that and not much more.
In your case, you'll be able to do the follow up and there would be less of it once you're on a stable warfarin dose.
What you need to consider is ruining your life for a few weeks now or waiting 10 years to ruin your life with a mechanical valve replacement. I can guarantee you'll bounce back from surgery a lot better at 61 than you will at 71, if you can even get the surgery by then. This is also something you need to consider.
Also, if you have the mechanical valve, you are going to need help at home. Hospital stays are shockingly short these days, you'll be up and walking as soon as you're breathing on your own and home 5 days later, average stay. You're not going to be ready to fend for yourself, there will be all sorts of activity restrictions for a few weeks. You'll need someone to drive, shop, take out the garbage, stuff like that.
Whickever option you choose, good luck and speedy recovery.