Start as early as you can. Make tapes of your characters.
There's a lot more to see when you're playing and because of the advances in technology it makes room for all kinds of new characters.
If I am not right for something there are many talented actors out there that will get it.
I usually have 10 different animation projects going at a time.
In general, I find that for videos the acting is more realistic.
I had to make squirrel noises as Bubbles and without realizing it, I was making the face and putting my fingers up to my face to look like a squirrel and everyone made fun of me for the rest of the day.