I would flower now if space is an issue. They are right at the maturity level where they are ready to show sex. If you wait another couple of weeks you will start to see preflowers. Also you might try to FIM them if you are limited in vertical space, but have plenty of horizontal space to work with. If you do FIM them make sure not to flower for at least 2 weeks after you make the cut so it can recover and not be in shock when you start flowering.