>>303907862d is making a comeback right now in a big way, but it's digital 2d. more on that in a bit.
in 2d you learn from the ground up.
in 3d you skip most of this...ok *deep breath*
I spent about a year and half grafting at the basics, starting with early early animation methods, pre-dating acetate cels. Just drawing onto copy paper. It's the way animation has developed, you have to learn archaic methods to understand the grounding and understand why things have change ect.
You will spend when you first get into it, as much time filling out little numbers and dashes on spreadsheets as you do drawing.
Animation is TIMING AND SPACING.
TIMING AND SPACING
TIMING AND SPACING
this will get drilled into your head to no end,
all the times I've spent drawing inbetweens and key frames and had my teacher say. frames 7,8,9, 21,22,23, 56,57,58 are off, go back and do them again, see if it works. for example.
if you can stomach arduous to know end repetitiveness, your looking into the wrong art form.
however , once you get over that first few months of heads down, pencils not even gripped, theory learning. You spend all your time watching old cartoons, experimental films and doodling characters in your work books.
the first thing your draw will be a bouncing ball. it'll be months before you get to draw anything with a face, but it'll be worth it...