Well in Australia i think you can get them at 16, too bad you don't live here.
Anyway, i'd use this method as it works for everything i've done so far:
Me: Hey mum can i get my ears pierced?
Mum: No
Me: Why not?
Mum: Ear piercings isn't for guys (just using the reason she gave you)
Me: I'm for equal rights
Mum: Well i'm your mum and i know whats good for you (or something idk)
Later on:
Mum: Can you help set the table?
Me: Am i worthy of that? Clearly i'm no equal to you since you've got your ears pierced and i'm not allowed
Then i continue like that, just asking if i'm allowed to. Occaisionally denying things i want, acting as though the decision is degrading my self esteem. Like:
Mum: Want an ice-cream?
Me: I would, but i don't think i'm worthy of one
Also, try to use statements in public to embarrass your mum so she'll get angry and let you get it. For example:
Person: Can you carry this for your mum?
Me: I'm not sure, i'm not treated equally like her so i'm not sure if i'd be allowed to carry that, i'd have to check.
Mum: *RAGING*