Actually it's not easy to say if young people still watch Pokemon. But I think that it's less popular now. I mean, when I was younger I loved watching Pokemon, the first seasons were amazing but then it started getting worse and worse, in my opinion. Nowadays, I seldom see any channel where Season 1 of Pokemon is on, where the real essence of the anime can be appreciated.
Although the Pokémon games are not for kids at all (they can be played by anyone, because you decide how complex do you want the game to be), I think the anime is for younger audiences. I mean, they focus on teaching the importance of friendship and another human values, which an adult likely (you know, there are all kind of people xP) has already assumed. Ash would die for his Pokemon, they help each other and they care about everyone. Those are human values which they're trying to transmit. The battles (most of them) are not really exciting and you can even foretell what's going to happen, or at least expect it. All these things make me think that the anime is perfect for younger audiences. Anyway, if you like it, it doesn't matter how old are you.