Some people call the start of flowering when they switch the lights to 12/12, others when they see proper flowers (not pre-flowers), others something different again. Me, it's when I see proper flowers, or I'll be harvesting too soon (I do not grow in a perfect environment, so can't finish as the seeds companies do with their perfect conditions, thus I add time at the end compared to them).
Regarding the plants, they all look fine to me, very fine in fact.