We were all rookies once, and all made similar mistakes.
I'm sure some instructors will use the wrong call-sign from time to time, especially on a busy day when changing aircraft.
The important thing is that you learn from the mistakes. I once started the engine with the fuel cock off. there was enough fuel in the lines to support a short taxi off the parking stand before the engine came to an abrupt stop. Took a little while to figure out, and very red faced infront of the girl I was trying to impress, but I've never done it since.