Go for it man. Worst that happens is that you wind up with an awesome degree or end up flying awesome machines of death and destruction.
As for the G's or fear of flying or whatever, unless your genetics are jacked up its all probably mind over matter so go to your local amusement park, throw in a big dip of copenhagen and start riding the rides until you puke your guts out. You'll either get over it or be scarred for life. YMMV, this is probably awful advice, don't listen to me. Or do. Point is we've all been there with big dreams and wasted so much time and effort "worrying" about the "what ifs" if we don't make it. Kick ass at everything you do, strive to your goals, and don't close any doors or burn any bridges.
As for the G's or fear of flying or whatever, unless your genetics are jacked up its all probably mind over matter so go to your local amusement park, throw in a big dip of copenhagen and start riding the rides until you puke your guts out. You'll either get over it or be scarred for life. YMMV, this is probably awful advice, don't listen to me. Or do. Point is we've all been there with big dreams and wasted so much time and effort "worrying" about the "what ifs" if we don't make it. Kick ass at everything you do, strive to your goals, and don't close any doors or burn any bridges.