When would you count week 1 day 1 of flower.?

Flowering is when there are small budlets forming and many clusters of white pistils. 12/12 is not flowering yet, just a change in lighting.

I put as day 1 of blooming phase the first real pistils, that are about 4-5 days after 12-12 switch. But it's up to you ;)

As soon as preflower sets in i believe, when you see hairs coming out here and there, but to be sure, when you see them coming from the budsites. Thats what i do! 💚🌱 good luck

just be consistent. I prefer to count days as they accrue, so on my little spreadhseet/calendar for notes and tracking info, i start with "day 0." a little calendar in openoffice calc or excel can be useful. initial date in first cell, call it a1 even if not), then a2 has "=a1+1", then fill down 100+ rows. can do that with a day column too. there is an autoincrement feature but by using the '+1' formula, it will adjust the numbering as you add or remove rows etc.. just "fill" in any gaps. the "fill" function will autoincrement any cell unless you put a "$" in front of either portion of cell address.

I consider it day 1 the day the lights switched

I don't really consider a plant in flower until it completes its transition, usually about 2 weeks after 12/12 is initiated. Others do day 1 of 12/12. Really no wrong answers, it's how you wanna journal it.