Combined Pill

Tanisha
I'm 17 Years old and in a sexual relationship and have been for a year. Its a long dis relationship aswell. Until recently, we have used condoms. I have been to the doctors and have got the combined pill. Although I did this behind my mum's back because she just didn't want me to go on the pill, but I no longer want to use condoms, but I'm definitely not ready to get pregnant. Is this okay? My mum is also transgender, which makes everything else more difficult. So is it okay to go behind her back and go on the pill, or do I need to tell her?