I've watched and re-watched Game Of Thrones many times, a lot of people believe that a season is a year, which it isn't particularly, in cases it could be though, but in Game Of Thrones it really isn't. Using a lot of math and statements given by characters you can easily discover a how time works in the show, and easy way to convey or show this is that two episode is a month, but of events in the harder way with a lot more math could mean 15-25 episode is somewhere around a year. I feel that the ages of the characters should be changed because of this, so far I think that it's only been two-three years from season 1.