Quick question W/pic

My girl is 5 weeks old now and the older fans leaves have a nice gloss or coating to them, the newer ones seem to have no gloss and just seems kinda dry, some leaves that are almost 2 weeks old still look dull and no gloss. There all the same color, and there is no other signs of trouble, i am pretty close to the light about 12" or little less, but she seems to like it.
I haven't started 12/12 yet waiting about 2 more weeks till the others are old enough to show sex, soil, miracle gro, 400 w MH + HPS, distilled and rain water very little nutes, already have about 6 preflowers, 18/6,
So basically why do my newer fan leaves don't appear as healthy, glossy, just plan nice as the older ones?

i would say because their just developed and will take awhile to produce the glossy buddin leaf look i couldent seee any pre flowers on the plant in the picture

dust. light changes. water changes. nute changes. wind. bugs. mad ex's. who knows bro.

Yah I would say if you are worried about the gloss of your fans you have nothing to worry about... I have never heard of this being a plant problem, ever.