First I want to commend you. You're disciplining your child, which is something that too few parents are doing these days..
On the shaving issue. I don't really get the too young thing. My beard started coming in when I was in 8th grade. I'm pretty glad my parents didn't think I was "too young" to start shaving at that point
The body determines when it is time to start shaving, not chronological age.
The biggest problem I see here are the night classes. You want the kid to be in school all day, and then she has to go to school again, only this time she doesn't even get to participate in the class, and she has to sit there, bored, until most kids should already be in bed. That's no way to be a kid. As I understand your post, you're only taking her with you while she is grounded, not all the time. If it's all the time then we have a whole host of other problems here.
But if my interpretation is correct, then you need to find another punishment. It's not healthy to sit at a desk all day and late into the night. She's been grounded, not chained to your ankle, and it seems to me that her crime, writing on a mirror with somethign that will (as I understand it - -- not having much experience with lipstick
) clean off easilly, is too severe. Couple reasons for that.
In the first place, it's overkill. Write on the mirror with lipstick, you're grounded for a few days, or you sit ont he stairs for an hour, or something. But it sounds like you've grounded her for a very long time, for a relatively minor crime. That doesn't give you very much wiggle room if she does something worse. What if she hits another kid? What will you do to make the punishment more severe? hang her upside down by her ankles? You can't ground her forever - after awhile, the punishment becomes so long that, with no end in sight, she doesn't have much incentive to behave anymore. It's like the prisoner who's in jail for life with no parole. There's not much incentive for him to worry about not committing crimes in there - what will they do? Give him 2 life sentences?
Also, grounding isn't an ideal punishment because children tend to respond better to the immediate rather than the distant future. A more immediate punishment would be better. I like the "instant chores" method. My kid screws up, he gets a chore. The difficulty of the chore depends on the heinousness of the screwup. This not only accomplishes your goal of having a negative consequence to her bad behavior, but it also gets things done around the house. The last time my kid screwed up, he found himself washing every window, inside and out, in the house (yes, it's a single story) and scrubbing the tiles (nasty little 1 inch ones with LOTS of grout) in the bathroom. Bet he'll never hit the dog again, which is my goal.