Hello, thanks for your question. If you are over 14, you do not need your mothers permission to start on birth control. Because it is a prescribed medication that can have side effects, it is best to find out as much information as you can about birthcontrol. You can talk confidentially to a nurse at a youth clinic about this and if you wanted to, you could bring your boyfriend or a friend with you. At most youth clinics, birth control pills are free.
For a listing of youth clinics near you see  http://www.vch.ca/your-health/youth/youth-clinics/ 
For more information about birth control you can call the Sex Sense Line  1-800-SEX-SENSE (1-800-739-7367) throughout BC* or 604-731-7803 in the Lower Mainland. or you can look at their contraceptive information on www.optionsforsexualhealth.org
Hope this helps.
Health Nurse