Interview Dress

Certainly no jeans. I'd say you have two options:
1: Navy jacket, grey trousers, white or light blue shirt, possibly with a stripe, neutral neat or reppe tie.
2: Navy or charcoal grey suit, the rest as above.
Black, decent shoes. If I were interviewing, any square-toed shoe would be an instant rejection.

A suit is never "not age appropriate". (I'm assuming you own a suit.)

I hate square-toed shoes more than most, but come on. You'd tell your alma mater that you can't recommend a 17 year old for admission because you don't like his (or his parents') taste in dress shoes? The kid should wear whatever dress shoes he has, even if they're ugly; he can buy "nice" dress shoes when he's interviewing for jobs as a college senior.

IMO Wearing a decent suit and tie is always appropriate from late teens onwards, and is never 'stuffy'. Own up to being the man you are, or should be. Straighten your tie, cut style and comb your hair, and shine your shoes then you should look pretty presentable.

 

Oh, and No, dont worry what the others are wearing, worry about what you wearing!!

Park Avenues are nice shoes, you'll do fine with those.

And this is an interview- if you have a suit, wear it. If you don't, wear a blazer. Tie is a must. Jeans of any sort would be a no. Stuffy is not a problem- this is a formal occasion, and you will be expected to dress formally. You're at an age where you would get leeway since many your age don't have a suit or much in the way of formal attire, but a coat and tie would still be expected.

I wouldn't wear a dress to an interview, a bit too fashion forward.

 

Go with a solid navy suit

+1

If the thread title had been, "Interview Attire," would you have said, "I wouldn't wear a tire"?

+1

 

Suits are always appropriate. I think especially at your age, you want to look professional and ready to work. One of my biggest fears with college aged kids, is you'll hire them and they'll decide partying is more important than showing up to work.

I can speak from experience here (I'm a college sophomore—did the interview thing when I was in high school). If you have a suit, you should wear it. Lots of kids interviewing will be wearing blazers and dress pants, though. 

To be honest, these interviews don't make that much difference and I wouldn't stress too much. They're looking to make sure you're not crazy, but I don't think they usually make or break an application. 

Best of luck! 

Also speaking from experience of both having had an alumni interview for an Ivy League school and having done alumni interviews for my alma mater, what jshastings says is right. The recommendation or report that will come out of this interview won't be a make or break component of your application. It might break it if you come off as a horrible person. Otherwise, this interview isn't going to get you in if you don't have the academic profile already in place (i.e. GPA and all that). In a sense, the interview is more of an opportunity for you to learn about the school by talking and experiencing someone who has gone there. It's in the interviewers interest to come off well too.

The arrangement for your interview is a bit at odds, to my mind. I would say that these interviews themselves are not terribly formal affairs; however, your interview is happening in a conservative environment (investment firm) so it is sensible to take your dress cue from there. The reason I say that the interviews aren't necessarily formal affairs is because they can happen a lot of places. I and other alumni I know (from Ivy League and other private universities) have conducted interviews at high schools, cafes, even our own homes at varying times of day--morning, noon, evening. Honestly, if a student was to show up at my home for the interview in a suit, I wouldn't hold it against them, but it could come across as trying too hard. I also wouldn't expect them to walk around in a suit all day at school if that's when and where the interview took place. Look neat and presentable, but equating this with a job interview is overkill IMO. You're still in high school. Your interviewer will care much more about you being a respectful, sincere, engaged, open, interesting and interested student than whether or not you know the dress code for their work environment.

If you showed up in nice shoes, slacks, a collared shirt and a sweater, I really think you would be fine. I personally wouldn't care if the person wore dark jeans so long as they were wearing something more than a t-shirt on top. If you have navy suit and Park Avenues and you're comfortable in it, wear that. At this point, more important than your dress is focusing on expressing your capability and character as a student and person, which I think you will do well given your cordiality in this thread.

Good luck!