That's not the average age how would you know. I think the average age is somewhat in the twenties though. Cause younger generations are more fond of bitcoins. So i'd say between 20-30 is where the most people would be located.
I don't think there is a certain age for Bitcoin users.
In my opinion it is more about having an interest for technology.
There are lots of guys in crypto space who are older than 30 years!
That's why I believe the actual younger, early 20s generation, is not definitely the majority of users.
But I could be wrong.It's my personal feeling.