Age Calculator with ARIA Attributes

What challenges did you encounter, and how did you overcome them?

One challenge I faced was checking if the date was invalid. What I found was that if the other input fields were invalid (i.e Day was set to something higher than 31), then both error messages would pop up. My solution was to do an initial check to see if any input elements contained the aria-invalid="true" attribute first, then check if the date was invalid.