At 12/12 consider yourself in preflower. You'll stay in preflower until after the stretch ends (1-2 weeks). After that I consider it the flower stage. It helps me to break it up this way. During preflower, the plants still want a strong veg nute mix, so it helps me to organize my feeding schedule a bit better by separating out preflower and flower.
For the purposes of your journal, I would include preflower as a flower week.