Best Way to Build an Online Age Calculator Tool?

Hey,

I’m planning to build an [url=https://agecalculator.ws/]Age Calculator Tool[/url] for my website where users can enter their birth date and instantly see their exact age in years, months, days, and maybe even hours. I also want to add some extra features like a birthday countdown and showing how many days a person has lived.

I’d love to get advice from this community:

Which language or framework would you suggest for building this (JavaScript, PHP, Python, etc.)?

How can I make sure the calculations stay accurate (e.g., leap years, time zones)?

What extra features do you think would make the tool more engaging for users?

If you’ve built something similar before, please share your experience or tips. It will really help me design a tool that’s useful and fun at the same time!