how can I tell someone I need to see a gynecologist?

I feel like I may have PCOS. My periods have suddenly become irregular as of April of this year, I have pain where my right ovary is located pretty frequently and I've noticed unexplained weight gain, an increase in hair on my abdomen and upper lip and brown patches on my skin. I ignored these symptoms until the other day, when I realized the irregularity of my periods. I feel like I really need to see a doctor to get some answers before it gets too far, but I've never been to a gynecologist. I'm only just about to turn 17 in a couple days, so I'd have to go through a parent or guardian before I do. I'm not close to my mom AT ALL, so I'm not comfortable bringing this up to her. I live with my grandmother, so I need to tell her. I just don't know how to bring it up. What exactly should I say? She's very conservative, especially when it comes to these things, so I don't know what to say. Any help at all would be greatly appreciated!