There is currently a 10 year commitment in the guard and reserves, just like active duty. If you really want a shot at a pilot slot in the reserves I would enlist until you get your degree then go to OTS. This shows some dedication to the military profession rather than just some guy or gal off the street who just wants to fly. I got 94 applications last time I had a pilot slot (Oct 10) to fill and ended up going with one of my Loadmasters that had gotten his degree and private pilots license. I cant remember how many apps I received the time before but once again I went with one of our home grown MX officers. Truthfully your 500 hours means nothing to the military. We are going to train you just like everybody else.

With that said good luck.