We’ve all felt that way when first going out, so don’t feel too scared or anxious. You’ll find that once you’re out in public, it’s wonderful! And if you smile and are confident in your appearance, no one will look twice, you’ll just be seen as a tall woman.
You’re also extremely fortunate that you apparently have the support of your wife. So many of us don’t, so feel blessed that you do.
One thing to try when first going out is to just drive around in your car. No one can tell how tall you are that way, and it gives you a stepping stone to get out into the world.