Going to be working at a highschool for a while and I need to dress appropriate
Most Helpful Guy
When you aren't sure, business casual style and carry some accessories to upgrade to a somewhat formal style.0
Most Helpful Girl
For work I recommend wearing a blazer along with a buttoned shirt. If you want to feel more comfortable you could pair it with a nice turtle neck. I would pair a turtle neck with a trench vest because it looks so good. Other good options are a trench coat, knit sweater shirt (preferably without drawings on it), those tie front coats that are trend today. Like the one on the picture below. These tops are good alternative to a parka during colder seasons. A good alternative to a t shirt during warmer seasons would be a buttoned up shirt.
For bottoms skinny pants are a great choice. You are young so skinny pants will suit you best better than any other kind of pants, while still looking professional, on top of that they're practical. They shouldn't be jeans, though.
As for shoes you would want something professional yet comfortable. Sneakers look too casual, heels can be uncomfortable. Flats, oxfords, and mini boots is what I would wear. In my opinion mini boots are the best, they're most comfortable and look the most professional.