It’s an aphorism. You could call it a metaphor, since the ‘path’ in question is not generally a literal ‘walkway’, but a pattern of thought. So the idea of a ‘path’ in thought is a metaphor.
What @WasCy said. I would just add that it is so obviously true that we probably wouldn’t classify it as an opinion. Most of us who have been around for a few decades to observe have seen wisdom come to us when we struck out on a new path.
I’d say it was metaphorical—a metaphorical expression of a truism—but I would not call it a metaphor. In fact, if I were going to be downright nit-picky about it I would say that it’s a mixed metaphor and needs work.
The use of “does” makes me feel that this is taken out of context. And I can’t figure out what the context is, so I would describe this as “Unsatisfying.”