Hi mate
If this is a auto flower you will start to see some signs of flowers whenever its ready
if not it will stay in veg till you change the lighting just remember to keep in mind the height of your room and remember that your plant will most likely double in size once you change the lighting so if your looking for a sign or a time to flip that would be it take in to account your space form the light to the plant as well
if that made no sense please forgive me i am high at the moment best of luck and well done with her so far she looks nice and healthy