Age Calculator App with happy birthday message

What are you most proud of, and what would you do differently next time?

I was able to do the validations and worked with dates in javascript which I haven't really ever done before. I was also able to add a little bit of extra stuff like a happy birthday text. Next time I would try to get the leap year accounted for, I just didn't attempt it.

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

The validations were hard at first because I had a lot of if else statements and there seemed to be too many cases to validate. I overcame this by starting over and doing it step by step, adding different functions so that it was cleaner code.

What specific areas of your project would you like help with?

per usual, is my code clean, or are there better and more efficient ways to handle things? Any redundancies?