be told to go write a project plan on a project im unfamiliar with when im still new here and unfamiliar in general

pain

Ouch

Tell them and ask for help.

Nightmare. Are you working for an external client or for a product company?

What I've heard from talking to managers at product companies is that - quite often they just want a general direction/vision as a guideline it doesn't matter if deadlines are missed or things end up diverging from the plan. It's still nice to write down some kind of ambition, even if it's not a strict requirement.

Yeah been there and if you take time they'll ask why it's taking so long as simply saying "I'm new to this project so will take time understanding and gathering data" isn't good enough, specially when other older team members are doing well in their projects :)))) good luck