Age calculator app with React & SCSS

This project was a lot of fun & I can't remember the last time I enjoyed the styling part of a project so much.

I am new to React & additionally this was my first time performing form validation and implementing a reducer beyond examples, so am very keen to hear any feedback about better ways to approach anything I've done or best practices I've violated.

I need to return and complete the bonus challenge item of animating the age result change. I've poked around at this but haven't delved into CSS animations on a good day, and would like to try not jumping straight to a React animations library first if possible.