If you knew your sight wasn't what it used to be,
If you knew you couldn't turn your stiff neck round far enough to compensate for your peripheral vision not being what it was,
If you lose concentration on journeys longer than local,
If you hurt somewhere in your body when driving,
If you find driving stressful,
If you've had a near miss or two
Would you still drive on longer unfamiliar journeys if you didn't feel safe to do so?
If you have trouble reading the signs at stations, hearing the announcements, or negotiating all the steps and keeping up with the crowds of people, doing all the changes, would you want to travel by train?
It's not anxiety in many cases it's a rational assessment.
Teenagers often overestimate their capabilities and underestimate the risks.
A few more decades of life experience recalibrates that.