When should a 2012 Honda Civic need its transmission fluid changed, or serviced? The vehicle has 83,000 miles?

Lots of highway driving for a three year old car. Drives perfectly, no problems, just trying to look ahead.

You are due. Most all automakers recommend a transmission fluid and filter change after 60k miles.

Check the owner's manual. It will specify the interval. Most likely, you are at least 10-20,000 miles overdue.