Wait, Ace. That's only once. The Queen of Hearts's rule #648: "One must brush one's teeth twice over after eating turkey." The housewarden even reminded us several times.
No wonder you have such a knack for looking after everyone! Thinking back, you've always had a kind older brother thing going on. You're always calmly watching over us. I can't even imagine you getting angry.
What, you never noticed? Even Riddle Me Fits leans on you. He just calls your name, and you're right there to fix the problem. He doesn't even have to tell you what it is. You're practically superhuman.
Each one has a specific use. One for your whole mouth, one for the back—stuff like that. The fan-shaped one is for scraping your tongue. And I use floss after I'm done, of course.
Teeth can't heal themselves once they've gone bad, so I say you can never be too vigilant. Though maybe I'm just more conscious of that fact than most since I grew up in a patisserie. Proper dental care was drilled into me from day one. Thankfully, it's paid off. I get a clean bill of health every time I visit the dentist.
Age is irrelevant when it comes to brushing teeth. With how often our dorms hold tea parties with sweets, I'd argue that getting the fundamentals down now is more important than ever.
Use gentle, quick strokes. No need for a vice grip on the brush, either. Hold it with the same force you would a pen. It's good you're taking it seriously. Brush it off now and you won't have any teeth left to brush later.