I suggest Unreal Engine, 11 years is old enough to follow tutorials on YouTube. I think I was at around this age when I played with Game Maker on Commodore 64.
There's not much coding required in UE, but there's some learning curve that's for sure. Having an instant feedback however is really good for learning.
I would also suggest https://www.rpgmakerweb.com/ which is a good for 2D RPG games, there are quite a few variants of they they released.
I’ve used Unreal Engine professionally for about 7 years and I would NOT recommend it to an 11-year-old, for much the same reason you don’t first teach people to fly in an Airbus A380.
I WOULD, however, recommend Unreal Engine for Fortnite (UEFN), which is stripped down and focused while still being powerful.
There's not much coding required in UE, but there's some learning curve that's for sure. Having an instant feedback however is really good for learning.
I would also suggest https://www.rpgmakerweb.com/ which is a good for 2D RPG games, there are quite a few variants of they they released.