Between sickly bouts and an unusual sleeping pattern, I've found myself hard pressed to get TLoU beat. I know one of my friends who is eager for someone to talk to about the game at length, so I'm curious as to how close to the end I am. I just got to the part where Joel falls down the elevator shaft and into the flooded basement, which serves as the game's first instance of real isolation, which is nice.
Note that the % indicator when you save (eg. try loading one of your saves to see it) is actually really damn accurate till near the end. It's only in the last areas that I thought it was jumping ahead faster than expected - but that may have been because the game seriously picks up as it goes along.
You are barely into the game, 45% sounds like too far.
And I would't frequent this board anymore right now, there are many spoilers that come from how the game develops that are bandied about on here like it were no big deal. I'd say you should probably not read anything at all until you hear the characters talking about bighorns. And then after that still avoid any topic which references the ending.