This is my first grow and I'm not sure when t...

Ya it's hard some times to pick when to harvest your babies we all look for milky tricohmes throughout and some amber as well depending on what high your looking for . The difference in harvest times is probably just genetics and every plant is a little different when it comes to harvest time ... I know my self that if I think they are ready to harvest that I would wait another week or two because impatience can cause you to chop when they should be left still.some people even chop what is ready and let the rest grow on still but with limiting space and a time line to run your girls it can be hard ... Best of luck cheers, they look healthy

I see you started counting flowering when you switched to 12/12. I always start counting when the first flowers are visible. The trichomes who are first on the plant are faster amber colored. I should wait until all the trichomes are full milky and minimun 10% amber colored trichomes. Good luck 🍀👍🏽