You don't even have to tell your mom! Planned parenthood or the doctor you usually go to can put you on the pill and not be allowed to tell your mother! It's doctor patient privileges....
It's always nice to have your mothers support, because sometimes by knowing what pill works for your mother will help determine the right pill for you. Also, just having family support is nice. Try to reason with your mother and provide her with positive facts about the pill that she might not know herself. Show her you are responsible about taking the pill, by starting out taking vitamins at the same time every day. But if that doesn't work, it doesn't sound like your mothers supporting to you too much.
If you decide to go on birth control give the it three months to get rid of your camps! The first month, there was no difference in m camps , but by the third month, I was completely cramp free!