Actually the days will not be 12/12 until the end of this month where I live and yet my plants have been budding since august. Indoors we use 12/12 as an ideal, but outside it works differently. It has to do with chemical ratios induced by light vs dark. It takes the plant longer but the process is more natural with less stretching. Likely your plant started budding around august. If it waited for 12/12 to bud it wouldn't finish until December or January for some strains.