Too Smart for School?

How much sense does that make? Mariah is chomping at the bit to go to school so I thought with us being back I'd put her in Pre-K. Sounds easy, right? Not so much. Apparently, she has to be tested and if she is too smart, there won't be a place for her. How do you explain to a 4 year old that they can't go because they aren't dumb enough?