Days are getting longer. The solstice is coming. Right now they won't be in flowering I presume. After the solstice you still have some more months before the autumnal equinox gives your balcony 12/12 of course it depends on the specific location of your balcony. Once it starts flowering is when you have to protect it from light pollution. If the only light pollution comes from inside your house you should put up a nice thick blackout curtain, turn on the light, and go outside to see if the light gets through. If there is light coming from out in the neighborhood you may need to put a tent around your plant or find some other way to keep it dark at night. But you still have time to go.