Is there a Mod / way to set the exact starting date?

[Flesby]

Hello everyone, I am watching a youtube let's play and try to play along.

However the  game I am watching begins on 12th Aprimay. When I set starting season to spring it starts at the 2nd Aprimay. When I select summer instead it starts at the 2nd of Jugust.

Is there a Mod that gives me the option to ste the exact starting date?