I wouldn't recommend Senaca for animation! I've heard negative things from quiet a few people. BUT!!! I heard all of this at Sheridan College, which means they probably never went there.
Seneca is kind of more of a party school, from what I've seen at their residence.
I would highly recommend applying for Sheridan college first! Everyone says its the best in Canada (maybe even north america) If you dont get into Animation, do art fundamentals first. Life drawing is probably the most important part of understanding human form and therefore animating it, and Sheridan has LOADS of it, 3 hours everyday even on weekends plus classes with a teacher or tutor. All for free! (except the tutor, i think its like $20 the whole semester!!)
Take advantage of it =)