You can flower it whenever you want really, after it's big enough to have a couple rows of leaves. You could veg a little while longer but it will still add height for the first two weeks of flowering.
I'd take out the light bar and get two more double CFL sockets like you have, and put them on both sides of the plant. The bar looks like it's too far away and half of it is below the pot where there's no plant. It's adding heat but not much usable light.