But while you are a student it is permanent'', even when you are not studying that hour/ day / week you are still a student. Try thinking of characteristics vs condition. I am an (continually) angry man vs I am a man wjo is angry. Life ´stages´are always considered characteristics in Spanish , just like ´soy una niña´---being a girl is a permanent characteristic while it is true but it won´t stay that way forever.
I know it feels. But in Spanish, "permanent" means continuing, if that even makes sense. Like how it's ella ES una niña, even though she will grow up.
Remember, all that Spanish people do for questions is raise their voices. They don't use Do you... or change the structure of the sentence, they keep it the same. Imo, it's easier that way!