You're definitely flexible enough for the squat jerk but there is some instability. It seems as though the instability may be coming from the shoulders. Try to start with your elbows further down and spread out a little bit (but still in front of the bar). On reps 2 and 3, it looks like you squat down too fast. Try to replicate the 1st rep and steady that bar overhead before you hit the bottom of the squat.
I would suggest trying some Clean Sots Presses
. Make sure you hold each rep at the top for about 2 seconds and make sure you're stable overhead before lowering it back down.
Slow this movement down a little bit. Make sure you're set before starting each rep. On a couple reps it looks like your weight distribution is thrown off a little because you're going too fast. The bar is close but it looks like you're pushing in out a little when you make contact because your arms are actively locked out. Keep your arms loose and let the bar travel straight up. So your elbows will break a little but that should only be from the momentum of the bar, not from pulling it up.
Also, you're coming up onto the toes too soon. Keep your feet flat longer and thing about jumping from the heels vertically. Here's a demo video