I had the impression that people married at different ages in the colonial era according to their social class. That is young woman from fairly prosperous, settled families mainly along the East Coast tended to marry later than did girls of farming families moving farther inland along the frontier. Of course, during the Revolution in the areas where there was the most fighting or where there were heavy recruitments, marriages were either postponed or occurred suddenly.
I wish there were books about Felicity's life in Williamsburg during the Revolution. That area was central to so much of what happened. An older Felicity involved with events at Yorktown would make an amazing story.