DEAR MISS MANNERS:I a tired of being treated like a child. My father says it's because I am a child--I am twelve-and-a-half years old--but it still isn't fair. If I go into a store to buy something, nobody pays any attention to me, or if they do, it's to say, "Leave that alone," "Don't touch that," although I haven't done anything. My money is as good as anybody's, but because I am younger, they feel they can be mean to me. It happens to me at home, too. My mother's friend who comes over after dinner sometimes, who doesn't have any children of her own and doesn't know what's what, likes to say to me, "Shouldn't you be in bed by now,dear?" when she doesn't even know what my bedtime is supposed to be. Is there any way I can make these people stop?GENTLE READER:Growing up is the best revenge.