Welcome to the board frankiee!
Yes, you can change to 16" rims but do you really want to do it?
You have to check with your dealer about the warranty.
Tire selection for 17" rims get better and better and already there is a great variety.
Why don't you wait for a year, see how the car is behaving for your driving needs and then start considering for changes, if needed.
Welcome again and many happy miles for you and your wife with your new Escape.