The schools I know of do not require it until you begin to solo, but they recommend you obtain it anyway. Here's why: the school's insurance which provides coverage in the meantime can have a large deductable which the student may be responsible for. In addition to any damage to the aircraft, there might also be lost revenue due to the aircraft being temporarily unavailable for use. You might end up having to pay several thousand dollars in damages, which could eat up the money you had saved up for your lessons. There could be any number of things that could happen. You might hit a parked plane's wing, or a gas pump or a building or even a person, with your wing while taxiing. Even if you don't end up having to pay a lot of money for damages, it could lead to conflict between you and the school or between you and another student or instructor. The insurance costs only about $200 a year. The AOPA has discounted rates for their members.

generally the flight schools include the insurance into the packages they provide. its actually allot easier this way, they take care of all the paperwork and such.  the general insurance is taken out on the actual plane you fly. i hope this answer helps. 

i have not yet joined a flying school, but thanks for the information Colton, i will be sure to check it out when i do.