Some people might think that adults have more of an advantage at protesting because they are older and that means they might know more about what they are protesting about. Maybe people think that adults will draw more of a crowd because they have a louder voice so people can hear from far away. However, what happens if the adults do something highly illegal to attract more people to them and then they get arrested for it?
Perhaps children might think that if they did something wrong they would be let off the hook because they are young. Although by acting in this way a child might show that they are irresponsible and that no one should listen to what they are protesting about. Because children are smaller and not seen as strong, it might be harder for them to get people to join in with their protest.
My opinion is that the children might have more of a chance because if they make a riot the word tends to get around. Just look at Greta Thumberg's achivements! And if you are famous just on the internet and you want to protest you could do it online to prevent any physical fighting. However, it could cause online fighting which is almost as bad.
The only problem is would the goverment approve the protesting? Although of course sometimes opposition to your protests just gets you more publicity.