I'm in the category of 30-39 years old.
This is the largest number of users. But I'm not surprised. At this age, people are mainly engaged in investment. Up to 30, usually everyone is engaged in training and marriage)
I also belong here and I beleive this is also the most productive group of Bitcoin users. By that age you usualy have some life experience, some funds to invest and some serious plans to achieve. It's good to see very many young people, almost kids, to join Bitcoin community but it's better if they have someone to guide them to prevent them from some fulish moves and decision. And I also beleive you are never too old to join the Bitcoin users world.