Congratulations on your decission!
The time frame can differ because of many factors. But, if there is a strong enough group of members they will be noticed.
Probably one of the shortest time framed beginnings was my local. Local began Fall Sememster of 1965 and Colonized Spring Semester of 1966. That was within the same school year.
It took 3 years to charter as certain requirments had to be full filled.
It can happen so good luck and go for it!
