To receive a TASC Pedagogical Certificate do I need to be in the program for three consecutive years?

 Although it is best to finish with your Collective, as long as you make up the part of the program you have missed, you can still receive your Certificate.

Do I need any prior experience to join a Collective?

You do not need any prior experience to join the Community Collective.  For the Educator and Certificate Collectives the prerequisite is some exposure to Creative Speech as well as some pedagogical experience and training.