Hmm. It's definitely good for older kids (your 13-year-old will be fine with it). I'm not sure if it may or may not get too complicated for your younger one (it's largely text-free, but there are symbols to learn: ).

It's been a bit since I've had a kid that young, but there's a series from Looney Labs called Fluxx that are a blast for kids, with lots of the chaos they tend to enjoy, but also work well for adults (and each game plays in less than five minutes).

We also used to love a game called Tsuro that's a gorgeous and simple game about building paths: