Weird question, but I just inherited a hat from my grandfather but don't know where he got it from. It's maybe ten inches tall, and I know the company that made it closed down in 1918, so it can't be from anytime after that. My great-grandfather would have been no older than 25 in this period. How likely was it that a 25 year old would wear a top hat in 1918?
What social class would your grandfather have been? Top hats were common among the upper class at that time, and 25 would be a reasonable age for a wearer.