why 100 days?

I have been so stressed out with work and past events (lost two pregnancies), that decided to take a new path to awareness and meditation, to find self-balance and inner peace/strength. I think that practicing during 100 days is a life changing challenge, and working out my worldwide and Hawaiian plus sacred and meditative dances everyday over 100 days is more feasible than 1 entire year..., at least for now.