How to ask to start!?

I am 16 and I have a regular period. I do get cramps that are kinda bad and I would like to start using birth control.

I don’t know how to tell my mom that I want to start! My older sister who is 18 gets the shots but she just started so I’m worried my mom will say I can’t start bc until I’m older.

I haven’t had sex but I have done oral and stuff so I’m also thinking that if I become sexually active that birth control would be a good thing to be on. Im obviously going to be safe and use a condom my first time but I want the backup.

Also, what time would be the best? Im leaning away from the pill because I don’t think I would remember to take them.

Any tips on how to ask my mom? Or if I should go to my doctor first? Thanks! Xx