This makes no sense

Some of the Gym Leaders are adults

That means they have more experience, and it is their job to train everyday to ensure they get stronger and stronger

So logically, they should be the top of the top of the country just behind the elite 4 and the champion

So HOW is it possible for CHILDREN to beat them ? It makes no sense, these children don't have enough experience which means they trained less, they can't make up strategies as fast as a Gym Leader, their pokémons aren't as strong as a Gym Leader's

The Gym Leader spent years and years to become more powerful, so it cannot be that one young child can beat them

It's not possible, this means that all their years of training is for nothing since anyone who barely even touched a pokéball can defeat them

That would be like a kindergartner beating a professional soccer player at a game

Does this make sense ? NO