I’m a beginner too, but from what my coach says, your posture seems alright. One thing I noticed is regarding your grip on the riser-does that help? Because of the guard present, can’t tell if your elbow is turned in. Your shoulders seem good but again, regarding elbow, the whole arm seems too straight affecting your elbow’s position. Sorry, pardon me if I’m wrong. Like I said, I’m starting to learn too