Your legs are hurting? Haha, Welcome to the club!!
You're not super old yet not a kid either. It depends on how you've treated your body so far in life up to this point. Were you in pretty good shape B4 you started HG...or are you out of shape and all the sudden, you've been thrusted into allot of training?
Carefull with TOO much stance work too early in your career.
** Give yourself appropriate rest times to counter(and heal) as much as your training. Build up to it and once your stronger you can go alittle apesh!t if you want to. One thing you don't want to do is over train and then start to make a mistake like hurt your knees or some other joints because of improper form or structure. Learn it right and be healthy.
** Are you a bigger person? Like over 6' and perhaps wiegh more than 200lb?
Size can be a problem. Not everyones joints are built the same and most bigger peoples bodies (ie Joints) cannot just be thrusted into Super Low stances just for training sake. AGAIN NOT everyone is built the same or can do the same.
Minor tweeks are adjustments should be allowed. That's how I teach. I favor and good rooted stance and training more the movement through the transitions. Not TOO low, rather what is just right and works. A good goal is to be healthier and stronger. Not to overtrain for macho ego's sake.
Be Safe: Nobody should force you to do what hurts beyond normal training or what is reasonable. IF something feels like its' Unhealthy or hurting your body or joints....Then it probably is. Not saying your school is bad, I'm just trying to help you look after your self and be healthy. You'll be glad you did.