Just graduated from the A&M nuclear program (May '10). If NUPOC is what you want to do for sure, I would recommend talking with the recruiter asap when you get to CS. Probably can't apply until your sophomore or junior year, which is good so you'll have all the Physics and Calc out of the way.
It'll look good if you do Corps and all, but I've never met an engineer in the Corps with above a 3.2 gpa. There's a reason for that.
If you have any other questions, you can PM me. When you get to CS, be sure to make upper level friends. They'll be an amazing resource for picking classes/profs and homework/tests. That can be said of anywhere, but especially true with A&M engineering core classes.
BTW, I'm about to go to DC to interview on 3/22 if you have any questions about app process and such.