It really depends what you want to do with your career.
With the convergence now of heavy media and useful content on line AE is finding its way into more and more design studios. I myself used AE for a client recently.
Obviously this is due to the reduced cost and wider availabilty of ADSL / ADSL 2.
I would consider where it is you want your career to go then choose a relevent course at your local college or university carefully! (And don't let them convince you to take a general course like a HND or BTEC).
Once you've decided on a course check out the student material and if there work is similar to what your looking to do, bingo.
Failing that spend 2 - 3 years with misguided tinkering, hard to follow books and Forums and you MIGHT manage to learn how to use the software before its obsolete!
Good Luck