Thanks. I appreciate your first-hand advice. I figure there are many who travel to Mexico/Mexico city with uneventful trip-—or even fun trip.
Tho my daughter has traveled alone in US, she just is not sure of what to expect at airport, etc. when traveling Internationally.
Wish there was a bullet list somewhere.
Other than the airport being ridiculously huge, there is nothing weird or special about it. One thing, do not under any circumstances lose the little tourist card you get. You must turn that in when you are leaving the country else there will be hassle. Keep it in your passport, and you should have it on you at all times.