When you are picked to join your team (work, sports, music, book club), you definitely want to make a good impression on your first day. So be the best you, you can be. There is no need to try and do something spectacular, out of the ordinary, bigger than life. You were picked for this team because of who you are: the skills you have; the things you do; your personality; your way of communicating.
Yes, you were probably also picked for your potential. But potential is future thing. It is gained by doing your tasks, every day; and getting better, every day. Potential is fulfilled with practice and learning and work.
So just take that first step and then the second. Just like any other day. Someday, you will do something big and splashy, if that is your role. And you won't even realize it is big and splashy, because you'll just be doing what you do best, being you.