Hey, Senistar. Nice plant! All your going to get are guesses to that question. there are lots of determining factors that contribute to a plant ripening early or ripening late. Your plant looks like a sativa, or a sativa dominant. Sativas generally take a little longer to finish. If I had to guess, I'd say you got about another month for that lady.
In order to truly be able to harvest at peak harvest time, you'll need one of these...
http://www.radioshack.com/product/index.jsp?productId=2179604 This Illuminated Microscope will allow you to see when your trichomes are at that milky or golden goodness.
Im not going to enter into the debate about whether you should or shouldn't trim your leaves. I will say that I've seen successful grows both ways. Your plants seem to be doing ok, sooo... If it aint' broke, dont fix it.
I noticed some browning on the edges of your leaves. this could be the first signs of nute burn, or a magnesium deficiency. Back off on your nutes for a week. If the browning, or "burnt" look doesn't fade, you may have a magnesium deficiency. To remedy that, you'll have to foliar feed your plant 1/2 teaspoon of epsom salts to a quart of water. Mash up the salt, put it in a quart of hot water (not boiling!) and let it dissolve...then foliar feed it to your plants (spray on the leaves, top and bottom).
Only do this if the browning of the leaves get worse. For the most part, Id say your plant looks healthy. A bit scrawny, but healthy nonetheless.
Hope this helps, man!