She’ll be shocked when she finds that most businesses expect you to dress appropriately for the job for which you are hired.
I provide my employees with polo shirts with the store name and logo on it. It is expected that you wear it while you are working. I am flexible about color and what bottom you wear with them. But you will wear the store shirt.
It was so customers know who to ask for assistance but lately part of it is that is helps to weed out the POSS's (Perpetually Offended Special Snowflakes).
You are not there to express your individuality. You are there to sell stuff.
That is what I pay you for.