Originally Posted by Ant-manic
mentally/behavior-wise, i'd say that he's in his early twenties.
I like that note. I'd personally argue mid-later twenties, but it gives us a good ballpark to say "Hey, if Thor isn't a 'god' as some seem to believe, because gods don't exist, and instead he's an alien (possibly from another dimension/universe, then how old will he live to be?"
Well, it sounds like he is already approx. 1000 years old. So if he ages in the same way as humans, he will likely live to be about 4000 give or take a few hundred years.