going vegan

Hey! I've been vegetarian for just over a year now and am wanting to go vegan but need to convince my mum to support me. She's hesitant to because I am extremely active and a teenager so I'm still growing but I'm 100% already committed I just need some points to help convince her. Any ideas? I'm already researching and gathering evidence so that she knows that I'm serious and will help out in the kitchen but I don't know what else to say? All ideas welcome!