if it were a photoperiod, i'd guess it is approaching 21 days from flip to 12/12 ... so if an autoflower, probably 14 days since you first saw preflowers. takes about 7 days for those preflowers to grow.
in the end you still have to let the plant dictate the schedule, so no worries..
remove any suggested flower time from breeder from your mind.. it matters not. observe plant. wait. be patient.