I wouldn't worry about the nom yet. Most do not close out their requests until October, and it is not a rolling nom, in other words we give out as they come in. They wait until that drop dead date and evaluate everyone at the exact same time. Applying in May is not going to give you an edge over the candidate that applied in Sept., actually it could hurt.
Here's a few reasons why:
1. Sending in the spring does not allow you to submit the most up to date resume.
2. You risk it getting lost or placed into the wrong file...i.e. they may think that you are asking for the class that they just apptd.
3. They are busy charging their cadets for this yr., and yet to know if they even have a spot to charge...they can only have 5 at one time.
4. They may change their reqs for next yr regarding materials needed to be submitted. Being ahead of the game may mean you didn't know about this, and now the file is incomplete, thus, no nom.
It is good to be proactive, just right now do well at SLS, at school and have the most competitive resume (missing sports, take one up, no APs register for some, low SAT. take the ACT) that will do more for you than getting in the nom paperwork 4-5 months before they close their date.
Good luck!