I know this isn’t a fashion advice forum but I 've heard first impressions are very important for the interview, which is why I was wondering what to wear. I know not to be too scandalous, but at the same time, I don’t really want to look like a grandmother. My outfits were going to be striped shapeless dress with a denim jacket and a black sleeveless blouse + A-line skirt with a cardigan. Neither of these outfits shows a lot of skin, but I’m worried about them being too casual.
What did you wear (or are planning to wear) to your interview? Also, what are some popular brands that have good clothes for the interview? Keep in mind I’m a teenage girl, who also doesn’t have a lot of money for clothes.
There are a ton of threads on this, so be sure to use the search feature but comfortable shoes are a must. And usually something you would wear to a nice dinner. Show your style though. An AO once told me how at entire inter they talked about a gives skirt, because she was into fashion and had actually sewed it herself. She was very shy before they discovered his face and it completely changed the course of the interview once the AO commented on it 
We suggested to our daughter to look on the school’s website to see what kids on campus are wearing.
Keep in mind that boarding school students are either doing their own laundry or having it assaulted weekly by a commercial laundry service, so the emphasis is on practical. We’ve also learned that most dress codes are more hopeful guidelines for parental consumption, not what kids actually wear.
We used to joke that “Preppy” really meant “Low cost of ownership.”