@FantasyChic I'm sorry but the only way into the school is by buying your way in or by getting a scholarship. Your character wouldn't be invited ever, they need to apply to the school.
Also, it's really strange that her parents dislike her using magic so much. This is a world where half the populace are mages and kids probably need training to make sure they didn't hurt themselves with their powers. It's also strange that the brother is so unadept that he apparently never had to worry about his magic getting out of hand. You can be unfairly talented in magic but you still need a bit of training to make sure you don't hurt anyone.
Speaking of magic training, most mages and every mage in this rp, wouldn't really have their magic manifest until they were 15, so their first year of high school. And every mage in this rp starts out only being able to summon their magical element. If she already has trained some then she would be far more advanced than anyone else in the rp, and especially self-taught and without a familiar that's not likely.