First off, flowering isn't about being tall enough, but being SHORTenough To me, as an indoor closet grower, flowering is dependent a lot on size requirements. Plan ahead so u don't run out of room is all im sayin. Ur plants gonna at least double in size during flowering. The new leaves will grow at will during flowering as well regardless of weather u let them develope before hand. Like silky said, no harm in more veg time (IF U GOT THE SPACE), more veg time = more buds in the end, but only if u can fulfill the need for more lights, more space, more everything.