It's a sativa dom or at least a sativa cross so maybe it will takes more time to get seriously into flowering than what you are thinking , of course the lake of light can be an issue and slow your grow but 12h of light is what a plant needs in flowering so no need to worry about that . I would personally have watch on the temps side as your day and night temps are not ideal , your day temps is on the lowest side of ghe average range and your night temps are not good.