We know Eb's wife died in/around 1810, per the timeline. Assuming that was Margaret's mom, then she was born no later than then.
That means she was at least 165 in 1975 when Harry is presumed to have been born, give or take a year.
By comparison, Donald Morgan was born in the fairly late 1800s. In SF he's described as being "about fifty years old". Luccio was born in 1800, 10 years earlier than the late Margaret age, and in DB she's described as a solid old matriarch. She would have been 205.
What does all that mean? Who knows, probably nothing. But if Harry is as powerful as his mother, and she aged better than her peers, then Harry should probably slow down on his aging now that he's around 40.