How do I tell my mom I want to see a gynecologist?

I don't have anything wrong with me. I'm thirteen. I have had my cycle for a while. Im just very curious about my sexual health. I've researched, and know exactly what will happen at an appointment like this. (only because it intrigues me. I may or may not want to become an ob gyn someday. ). Also, I need a dr. to show me how to do self breast exams. Video tutorials aren't working. I'm embarrassed to ask, and afraid she'll say no since money is tight. Any ideas? Thx.