As a junior developer, your primary goal should be to learn and absorb as much as you can, not to try to make a name for yourself. It's all too common that I see devs fresh out of college with this amazing gung ho attitude that quickly devolves into needing to feel like the smartest person in the room.
This leads to an unnaturally inflated ego, a feeling of self importance, and blocks you from truly understanding what is going on in the stack in front of you.
That's not to say you can't try to take on difficult tasks, just be humble and ask for help when you need it, and don't make assumptions that might lead to rework later.
I would much rather you ask me a question then put up a PR that has wildly different assumptions because you didn't fully understand the acceptance criteria of a particular task.

tl;dr - sit down, shut up, do your job, learn what you can as fast as you can.

Sincerely,
A very fed up Senior Dev