Not really support, but couldn't find a better place to post it on. Is the day counter (when you press f3 on left side) bound to your profile and so, even if you switch machines, will it transfer? Because I haven't even had my current pc for as much time as the ingame timer signals (and I know it's 20 minutes per day).
That shows how many days have passed in the current world, independent of any other worlds or computers; there is no data saved to your online Mojang account other than skins and usernames and whether you bought the game, everything else is stored locally. Also, the day will advance faster if you sleep (down to 10 minutes per day if you skip the entire night) as it only measures day/night cycles, not the total time (which will be shown in the statistics, which are again for the current world only).