How close to harvesting?

Can anyone give me a approx how many weeks left until I should harvest this girl?

at least 3 weeks to a month

Probably a month or so, they are looking good so far. Now is the hardest time of your grow to be patient and the most important time to be patient. Watch your plant for signs she is finishing, pistil turn colors and shrivel, fan leaves yellow from the bottom up among others. I would suggest buying an inexpensive microscope about $12 at radio shack and check your trichs as you get closer. Doing this you can harvest at the best time for the high you are trying to obtain, energenic heady to couch lock. Here is a link made by fdd2blk to read to give you more information so that you can make an informed decision.

https://www.rollitup.org/harvesting-curing/28072-harvest-time-tutorial.html

Good Luck with your harvest