We were planning to start piano lessons with her this summer, but after winning a basket of beginning piano books from the school carnival silent auction , she didn't want to wait. We thought that since daddy was going to be a music major once upon a time and is so musical that he would start out teaching her. I talked to some piano teachers around us and they don't start individual lessons until age 7, but do have group lessons for ages 5-6. Although, the group lessons are general music lessons and not specifically piano, which is not what we wanted.
She has started to learn how to play Happy Birthday as well, for obvious reasons. She asked to learn it that day, so she wasn't very proficient for my birthday, but after a couple more times I think she will do well.