>>7618543 (OP)You don't have to pick only one, since they all sort of blend together.
Pick up blender, and learn enough to start getting good at grease pencil - then start learning how to animate, and do so in blender.
But wait, as you're animating, you're drawing!? Now you're going to be getting better at all three, wowee!
Granted, this has something of a limit on it.
You're not really studying drawing, so you'll hit a wall skill-wise if you don't actively trying studying it, but if you're happy with just cartoon drawings for your animations, that's enough.
If you're not incorporating 3D into your animations, you're going to stunt in that area as well, but you'll still know your way around the program.
The only area you'll really continuously improve in is your animation skills, but that's only if you push yourself and animate more than just talking heads and stiff pose to pose shots.
But anyway, if you want all 3, you can have them, but 2 will be more neglected than the other.
