My boss thinks I could be promoted someday?

well, last night, I was being left in charge of "zoning", which basically means making sure the shelves are clean, neat, and that the product is as close to the lip as possible. While this was going on, my supervisor told me that the reason why she was pushing me hard on getting it perfect was because she believes I have the potential to move up into a supervisor's role, should I wish to make that a goal. So I told her my long term plan would include me doing a less physical job, and she said she would talk to people and see about getting the ball rolling for me toward that end.

I'm kinda stunned. I've never been good enough at a job to have someone consider promoting me before ....