The first time I strapped on an O2 mask in the back seat of a T-28 on a BI flight, I said to myself "What the hell have I gotten myself into?"
The first time I tried on my newly issued torso harness in preparation for FAM-1 in a straight-wing night radial interceptor in Meridian, I said to myself "What the hell have I gotten myself into?"
The first time I spent a few days "stuck" on a carrier, after weather moved in during the middle of CQ in TA-4Js, and thought I was gone to die of boredom, I said to myself... well, you get the idea.
My advice in regards to the mask...deal with it. You'll eventually get a better fit, you'll get used to it, and you'll find more important things to bitch and/or worry about.