First time as a mid-level and am not sure what to do

hi.

I have 3 yoe (just for company size context-all in big banks), 1.5 of which were as an intern at 2 different companie. the other 1.5 were at non-tech roles. after a few rounds of interviews for another junior now full time position, I was surprised and supper happy to be offer a mid-level role. Its been 2 weeks into the new role and everyone is super cool and the project is super cool. but i keep thinking and wondering if they made a mistake hiring me as I have 0 idea how to "act" like a mid-level as in previous roles I always interacted with senior people. do you have any tips on the transition into a higher responsibility role? what is it to be a mid-level?

thanks