See this question and this answer.
Star Wars and E.T. are in the same universe. Members of E.T.'s species appear in the Senate chamber in Star Wars Episode I.
The humans that appear in E.T. are at least roughly the same size, relative to E.T., that the Star Wars humans are relative to the folks from Brodo Asogi in Star Wars.
(The idea of Star Wars and E.T. being in the same universe almost certainly started as a joke, but according to the linked answer, Spielberg and Lucas have put enough canon information in both universes to confirm it.)
Conclusion: Earth humans and Star Wars humans are close to the same size.
This assumes, of course, that E.T. takes place in our universe; we see more than enough information in the movie to confirm that that's the intention. It's conceivable, I suppose, that E.T. takes place in a parallel universe with a different scale, but that's not particularly plausible.
There are also physical problems with having human-shaped creatures of significantly different sizes. We've seen Star Wars humans walking around on a number of different planets, and they always appear to be moving normally. A human-shaped creature that's say, 10 meters tall would move very differently, assuming he could even support his own weight. Lower gravity could partly solve that, but then such creatures would have to move more slowly, and we'd have to assume that the movies are shown with a different time scale. Similar considerations apply for smaller human-like creatures. And we'd have to assume that the Galaxy Far Far Away is full of planets that appear Earth-like, but that consistently have substantially different surface gravities and breathable atmospheres.
(Personally, I like the idea that the "humans" in Star Wars are not human at all, that they're some random alien species that happens to dominate the galaxy, and they're portrayed by human actors in the movies for the sake of storytelling. But the E.T./Brodo Asogi connection probably contradicts that idea.)