I think that age doesn't matter here, cause if you like something, you should do it, or if you don't have any other opportunity to earn money...
I agree with the age, but in reality there are age limits who can afford or even start this type of income.
Well bitcoin does have discrimination about the age. As long as you can use it and you can earn bitcoins then that is fine. And even old aged people does really need to earn with bitcoin if they want to so that they are going to have something to earn. They must be treated same treatment as the young ones are getting in the society.