16?
At 16 (admitidly close to 17) I organised and booked tickets for myself LHR - JFK - Pittsburgh - St. Louis. then back St Louis - Pittsburgh - Rochester, NY - JFK - LHR. All on my lonesome.
I do think that perhaps there is a certain lack of self reliance going on here.
Check in - go through security - ask nice security man/woman where to find the right gate - go to it(so that in your mind you know how far it is/where it is) - go back to shops - spend all your holiday money..... OK don't do the last one! Keep an eye on screens - go to gate when it says to.
To be honest I find a bus timetable more confusing than airports.
Don't be frightened of the world, most people are happy to help. If you (or the young lady concerned) have been conditioned to think that every stranger is a potential rapist/thief/con-artist that is all they are ever going to find!
At 16 she she should be well able to negotiate an airport - it is certainly not the airlines responsibility to sort her out (unless large fees have been paid for the privelege)