Hi JM9 -
I always thought my long, straight, thick hair (LOTS of gray in it now) was my best feature as far as appearance goes. However, even as a reservist, I found it way easier to keep it short. Faster in and out of the shower, cooler during field training, no hair emergency when the bun pins/ponytail holders broke or dislodged, headgear fits consistently (Big one if it is sized and fitted to your head. Nothing like a wad of hair under the helmet support netting during rifle qualification to give you an unimaginable headache.) ... you get the picture.
So my 2 cents - try pinning it up, but spend some time this summer researching a hairstyle that works with your texture of hair - and the time you are willing to spend styling it - so if you change your mind you can implement it quickly.