From what I know. The "Joined" under your profile picture in forums. This is the day you made an account on MCC's website. To get an exact day of joining the game's server, I believe that's something only admin have access to, perhaps?
Hey there, As Leyton said yes you can view the day in which you joined the website, however there is no way of knowing what day you logged in game for the first time sadly. [Answered - Locked]