It's growing nicely!! I don't think I've even seen a plant with leaves that wide. That is a heavy indica for sure and at most a 8 week flower.
A 150W puts out about 16000 lumens. Not sure how big the plant will be if you flower now, (25" ???) but lets just say 2'x2' for example. That is 4 sqft.
16000 / 4 = 4000 lumens per sqft
(3000 - 7000 lumens per sqft is a good range)
You've got just over the minimum. I say flower them soon and get some CFL's for side lights.
my humble opinion
I wait a week after a fim to let the side growth come up to meet the light. I also flower at about 5 weeks or when I have alternating leaves. Your grow, your call.