Being unable to get your foreskin down at 12 is not
medically abnormal. This is entirely unnecessary surgery, and you should stop seeing whatever doctor told you it is. Tell your mom this. About half of uncut guys can't retract at 12. Give it a few years, let it happen naturally (tug in the shower some), and if you still can't, there is a steroid cream that cures up 80% of cases.
Get your mom to read these:
(You don't have phimosis, even - just an unretractable foreskin. But this shows that, if you do end up with it, there are better things to do than circumcision.)
There is no need to go through, and pay for, this surgery. There is nothing wrong with you. Again, your doctor is seriously
misinformed (with all respect to him). Tell your mom to cancel the circumcisions and give some time to research this. It's your body; you have the right to not be subjected to unnecessary, and potentially dangerous surgery for no reason.
Good luck. Feel free to ask if you or your parents need more information.