I am 65-70 hours in, haven't even started the MQ yet, only started the Companion Quest line and am only a few missions in! So what have I been doing all that time? Exploring of course

I am worried now I have explored a little too much and they might start sending me to places I have already cleared, so I guess I should start to do the questlines

Not sure what Pete stated was the amount of 'Places of Interests' in Skyrim to visit, but according to my gamestats I have found 135 already! I have always played the TES games like this, just do Side-quests until I feel I have explored enough of the beautiful land then tackle the bigger ones!
Totally loving this game, and still finding new things and places even after all that exploring on foot!