As for Objectivism being practical, it depends on what you want to accomplish. If your goal is happiness, then Objectivism is immensely practical. It may not be all that practical for getting an A on an English paper in a class run by a pseudo-socialist, but grades given by someone you don’t respect are far less essential to your happiness than your integrity. (or they should be) What would make you happier: getting a A on a paper about how wonderful socialism is even though you don’t believe it and don’t respect the teacher, or getting an F on a paper about the power of the individual and knowing that you are right no matter what your teacher says? If your choice is the latter, you need not worry about the practicality of Objectivism.
I partly disagree here. A proper application of Objectivism is always practical. There are more options available to Tim than getting an A on a pro-socialism paper and an F on a pro-Objectivist one. In order to decide your proper course of action, you need to consider all the facts available to you. It is in your self-interest to get an A if going to a good college is your goal. It is also in your self-interest to write a paper without compromising your integrity. Why write a paper that endorses either philosophy explicitly. I like the idea of analyzing a current even that appears controversial but really isn’t - like the Schiavo case, as someone mentioned earlier. This case has caused a tremendous uproar, and everyone seems to have an opinion - it’s something your teacher expects you to take a stand on. But, by the same token, because people are so divided, holding an opinion that conflicts with your teachers isn’t as “controversial,” because many, many people will agree with both of you. It’s kind of using your teacher’s social subjectvism in your favor. He seems to place value in mass-agreement (most socialists do; correct me if I’m wrong). I would wager he’d find a disagreement on highly controversial issues such as these far more acceptable than the ones where “everybody knows” such-and-such.
Ask yourself this: What value did you hope to gain by turning in an explicitly pro-Objectivist paper? Did you hope to convince the teacher that Objectivism is a correct philosophy, or were you trying to get a good grade? Was this really a good way to go about either, or whatever value it was you were trying to gain?
I’ll give you some advice. Don’t preach Objectivism to people who haven’t asked to hear about Objectivism. Do let the people you value know that you are learning about a philosophy that is just about the best thing you’ve ever heard, and answer their questions when and if they ask them. But I would advise against trying to “convert” everyone who crosses your path. You are probably feeling something along the lines of: “There really is someone who understands! How wonderful it is that Ayn Rand was able to put into words everything I’ve always felt, but couldn’t identify!” Not everyone feels this way; most do not. There is no value to be gained from “preaching” to those who aren’t interested and refuse to listen. You have already observed some of the negative effects this approach can have. Think of all the values you are missing out on - a good grade from your teacher, friendships with peers who surely have some value to offer, but are put off by what they view as dogmatic ramblings that go against what “everybody knows.”
As far as going to an administrator is concerned, pick your battles wisely. Again, what value is to be gained? From all the information you’ve given, it doesn’t appear there is any (although, only you can say for sure). Once, I had a Spanish teacher who would argue with me in class and berate me in front of other students for being atheist. I said to her, in front of the whole class: “I am in this class to learn a language, not a religion. I suggest you stop preaching to me immediately, or I’ll get my father involved. He is atheist, and very hard to deal with. I seriously doubt the Principal, your boss, will appreciate the extreme inconvenience of dealing with him when he’s in a temper, and this would infuriate him.” The result was that she stopped, my classmates chuckled under their breath and I gained the respect of my peers and myself. Now, I am absolutely not suggesting you take a similar approach. It could have catastrophic effects depending on the circumstances, and in hindsight, I can’t believe I took such a risk.
The bottom line is that all of your actions (in school, and elsewhere) should be guided by the answer to the following question: What value am I trying to gain and/or keep, and which action(s) will be most successful in doing it?
Keep studying Objectivism, keep pursuing your values, and don’t give too much attention to the irrational - the irrational has nothing to offer you. 
. And please don’t think I’m criticising you in this regard. I am not.