Unexpectedly got a teenager. What do I do with it?

This past week my 12 year old niece moved in with us and I now have power of attorney. She has always made wonderful grades because the family friend she lived with would drill her constantly on math questions she missed. Her texts and apps were constantly monitored, she was never allowed to have SnapChat or Instagram or TikTok.I’ve always been close to her and we have talked about nudes and sex before, she knows nudes are dumb because they’ve ruined lives even at the middle school level. And sex makes babies and she doesn’t want kids. I’ve always told her birth control and condoms are the way to go if that is sex is ever a possibility. She’s a cheerleader and just likes to hang out with friends and go skating and make TikToks and watch YouTube.I’m a teacher in her same district so I gained access to her grades and I’ve been emailing her teachers. One teacher today told me she gets distracted by talking in class.Now I’m stumped because how do you discipline a teen logically? We have always had open communication bc I’m her aunt and I don’t want that to shut down- she tells me who vapes, who smokes weed, who has sex, who throws house parties, etc. (and she disapproves of those).Also, what kind of chores should she have?What kind of allowance should she get? What’s a good clothing budget? How often do you buy clothes? When do you buy all the stuff they like to have?Thanks in advance for any advice!! Edited to add: she’s never had chores before because her only chore was to get good grades and drill math. She was paid for grades. via /r/Parenting https://ift.tt/2KzmfuD