Sativa just takes longer to mature. You seem to have a really long maturing Sativa though. The reason folks still grow sativa - blue dream, pineapple, white widow, pineapple express, sour diesel, lambs bread and other varieties of sativa are absolutely killer. Pineapple and Mazar-i-sharif are varieties that may not mature until november, december or january outdoors. No matter how good your weed is you get used to it if you smoke the same thing all year. Variety is the spice of life.