Avery, this is a common concern, but you really have to understand that you have placed yourself into the classic Catch-22 situation (look it up if you don't "get" this reference, or if you haven't read Heller's 1961 novel): you want your nose to look different than it does now (and this should be because YOU want the change, not because OTHERS have teased you, etc.), but you don't want anyone to notice because "it won't be a very fun year for you." So let's see if I got this right . . . you want your nose to be different but you don't want anybody to see the difference so they can tease you about it? Is THAT what you mean?
Easy solution so nobody will torment you about having had rhinoplasty--Don't have rhinoplasty!
But of course, you don't want to keep the nose you have now, and you perhaps are hoping rhinoplasty will magically transform your senior year into, well, something better than it otherwise would have been with your "old" nose!
And do you really think dyeing your hair another color will do anything but tip people off to look for what you're trying to distract them from? It will just make them look harder, and BTW, the difference is right there on your face!
(One other point, if you were my daughter (one of whom who actually now teaches high school English), I'd NOT pay for rhinoplasty if you REALLY think the purpose of your senior year in high school is to "have fun." You know what I mean!)
But back to your concern. It's real, and I DO understand where you're coming from, better than you think from reading my joshingly sarcastic answer so far! My oldest (other) daughter complained about her nose from about the age 12 on, and her dad (me) had the surgical ability to give her the nose of her dreams (or at least get rid of the big schnoz she inherited from me)! She also worried about what others would think, and I really thought she wouldn't go through with it when the time came to go ahead. Or, if she did, I thought she would "hide out" until the last bruise was gone, and not even be seen in public or by any of her friends until everything had COMPLETELY settled. Boy, was I wrong! When the time came she jumped at the opportunity to fill an open slot in my surgical schedule, and she went out in public the next day, splint, tape, bruises, and all! She has never regretted going ahead, and has a lovely new nose that no longer looks like her dad's!
So, Avery, you have a simple choice. If you want a new nose, you shouldn't try to hide it by coloring your hair, and if you "tell" even one friend, everyone will know anyway! I'd start by owning up to your new reality and telling all your friends. Now. So when the time comes, it's Ho-Hum OLD news.
Otherwise, wait until you graduate, and have your rhinoplasty before you start college. And concentrate on getting good grades this year so you get into the college you want! Trust me, at your 10th high school reunion nobody will give a rat's hiney or even remember you had a rhinoplasty or a "fun" year. It will be about where you are in your career, life, relationships, and perhaps children of your own. The "nerds" who got good grades, good jobs, and the great spouses will rule, and the jocks and mean girls will be fat and balding and working at the local dive!
So although this started out as a question about rhinoplasty, it's an answer about priorities. Get that right, and the rest falls nicely into place! Best wishes on an awesome future (with a new nose--whenever you get it)!