I've had this issue in a story I'm writing, because one faction in this story is fighting for a cause that's essentially good, but they've become extremely jaded by lack of change and have resorted to extremely violent measures. So it's obvious the government they're fighting would call them terrorists, but a hundred years later, history should view them with reserved optimism. It's hard to categorize how the narrator and heroes should view them though, since the heroes don't necessarily directly cooperate.

Yep.

This and virtually all countries were founded by people who would fit the definition of terrorist.

How history remembers you is solely on the basis of how successful your "terrorism" was.

George Washington is a very well regarded terrorist in modernity.