I was squatting until I realized that my formed sucked and I was hurting my left knee. So I decided to build flexibility/mobility and one way is the third world squat.

I really want to be able to do the third world squat and I suck at it now. I practice it (holding onto things, goblet squats, going only partially down, etc) frequently but my knees and hip flexors are starting to hurt. Is this bad and should I stop?

How frequently should I practice this? Will eating a lot help me with recovery?

Finally, I really suck at this but I want to start squatting with weights. really I just don't want to wait until I can do it to start with weights. Is this a bad idea? How flexible do I need to be to squat safely?