My oldest Dd started ballet aged 2. Remember having a rather disgruntled dh who thought I was trying to live my life through dd after her first lesson. Now she is ten, eagerly awaiting the word from her teacher that she can get her point shoes and dances every day of the week apart from Thursdays, when she has a singing lesson.
It was probably when she was three, and was picked to do a special bit in her second show that she got bitten by the bug and she regularly takes part in local dance festivals, pantomimes, shows and even works professionally and gets paid.
Her little brother started joining in at ballet before he was two. He is six now and already says that he is going to go to full time dance school when he's eleven. He also does festivals and loves being on stage. I feel, as a boy, he has almost had more opportunities than dd1.
Ds2 started ballet at about 3. He has stopped and started a bit but currently attends 1 ballet class and 1 street jazz lesson a week. He does the annual show but has no interest in performing other than that. That's fine, he enjoys his classes but we won't push him into it anymore than he wants to do it.
Dd2 is four next week and has already started dancing at festivals. She has already won medals for second place and shows every sign of following in her big sisters footsteps. She loves the limelight and really enjoys being on stage. She also started at 2.
That said, my children are not the norm. We have lots of children at the dance school that attend 1 class a week and really enjoy their classes but have no interest in performing. Our teacher who takes the tiny classes is lovely and I swear a lot of girls only come to see her! I have never, in 8 years, heard her raise her voice and yet my oldest is most upset if she feels her teacher is disappointed with the effort she is putting in.
Ballet is a great thing to do as a child. It is very disciplined, helps with poise, balance, Rhythm, coordination and friendships. I never expected to still be there 8 years after starting my first dd, but it is a way of life for us now!