Well, you can apply to west point as an enlisted soldier so this gives you an opputunity for a service connected nomination, but if you are not admitted you will still be a guard/reserve member (which inst necessarily bad).
I am thinking about doing the same thing, you really have to talk to a recruiter. It will give you another opportunity to get a nomination, and have service experience before the academy. But you also have to know that you will be a soldier (Not a bad thing at all, just something to think about).
i did join the reserves at 17...and it really did help me because i was able to get away from the political nominations and all that hassle all i had to do was ask my company commander to fill out a nomination that west point provided me with and i sent it to admissions...and plus going to basic and getting use to the military lifestyle will also help because beast won't be as much of a culture shock. so it is a very good idea and it is an easy way to earn some extra cash for your senior year.
I have been talking to my recruiter, and others of course involved with West Point. I have found the recruiter doesn't really care if you go to West Point or not, but he/she can help point you in the right direction to getting there. He/she can also give you all the advantages and the disadvantages. However, if this is for sure what you want to do, no matter if you get into West Point or not there are really no disadvantages (arguable of course if you think you could be doing something better with your time).
I believe I will enlist. July 20, 2009 is when I turn 17.
Talk to a representative of USMA before you make a decision. They, unlike the recruiter, are qualified to guide you on the path to West Point, and certainly have a better idea of how to make yourself competitive.