When I was about 20 I had a job interview for a front-end dev position, I started taking their test and they asked me to write out an HTML form with some inputs/buttons and form actions on.
I had no idea how to write a form.
How I dealt with it:
The interviewer left the room, I googled "HTML forms" on my phone and miserably failed the interview.
What happened next:
I mastered HTML forms :D