New to lifting: squat form check.

[Laplace's Daemon]

I began Starting Strength in January, beginning with a conservative 75lb squat. For about 3 weeks I made linear progression on the squat up to 135lb. Then I made a video of myself and noticed that my back was quite round at the bottom. So I spent a few workouts at light weights, and I've started doing hamstring stretches three times a day.

On Monday's workout, I was filmed doing 2 sets of 105x5, at the Youtube links:
http://www.youtube.com/watch?v=7j-W-D-cI_g
http://www.youtube.com/watch?v=WB23Qpz_mzw

My questions:
1. How bad is my form?
2. What should I do to fix the mistakes (I assume, I will be working only with light weights until it is fixed)?
3. If I am only working with light weights on the squat, is it still worthwhile to GOMAD and eat big?

[Mark Rippetoe]

Your form is not that bad, and working with light weights to fix it is a waste of time because heavy weights are where adaptation occurs and where form matters. Learn to arch your low back, and keep it that way when you train. When you get strong that way, you will be using good form at heavy weights.

[caseyd123]

Holy shit thats where I lift! Hey we have a little group of about 5 students working on the barbell lifts in the SS model, I am the 'coach' but wouldn't really call it that I'm only 19. PM me if you want to train together sometime! Always glad to see someone else working on the bb lifts

[Robert Callahan]

The biggest thing I saw was you are letting your chest drop at the start of your decent into the squat. Think about puffing your chest up and keeping it like that throughout the movement.

Looks a lot better than many beginners I have seen!