Normally I'm a carry-on-only advocate, but in this case I would make an exception so there is less stress over what can go through security and what can't. Also first timers usually think they need much more stuff than they actually need, making carry-on-only a challenge. Pack all medications and other difficult-to-replicate essentials and a change of clothes in a small carryon and check everything else. Sign up for flight alerts the day before. Plan to arrive at the airport extra early to reduce anxiety over unforeseen delays on the way to and at the airport. Once through security, find the gate. Then relax. If not sitting at gate, check gate status occasionally for last-minute changes. And pee before boarding.