It can cause irregular bleeding for sure. It's not normal to have your period every two weeks as will end up happening if your body responds to being off the pill the way most women's bodies do.
I would ask your mom to please take you to the doctor and discuss it with her. Remind her her friend is not a doctor, and the doctor knows best. Tell her you are open to her voicing her concerns to the doctor about taking the pill as he or she directs and asking the doctor to explain his or her reasoning for having you take the pill the way he or she directs.
Besides, you're on the pill to avoid more cysts growing with PCOS, right? Definitely not good to mess around with how you take the pill compared to what the doctor says.
It's not dangerous except that you will have zero protection from pregnancy plus manipulating your hormones that way will cause more irregular bleeding problems. Your mom's friend is clearly not educated at all on proper pill use and literally doesn't know what she's taking about. Your mom is not too bright either if she believes that nonsense.
How does she force you to not take it? Does she hold the pack and just give you a pill each day? You're old enough to carry the pack yourself and she should not be treating you like a baby who isn't capable of taking your own meds. I think you should definitely call your doctor to talk about it and get her to educate your ignorant mother on proper use of the pill.