first gyno appt. but I don't want my mom to know I'm sexually active!

Hi ladies. I went to have my annual check up at the doctor today and I mentioned how horrible my periods are and my doctor told me I should 100% for sure see the gynecologist and get on birth control. So the thing is that I'm only almost 17 and I'm also sexually active. I'm very responsible about it and I always use protection but my main concern is about my mom finding out. I'd really prefer if she didn't know, so do they ask you that question when a parent is in the room? How does it work? I've never been to the gyno before so I'm a little clueless lol. Thank you all so much for the help! :)