To check the age of a domain:

Use a WHOIS lookup service online or via your terminal.
Search for "domain age checker" and use an online tool.
Visit the domain registrar's website and use their WHOIS or domain lookup tool.
Explore dedicated domain information websites like "whois.net" or "domaintools.com."
Enter the domain name to retrieve registration details, including the creation date. Keep in mind that privacy settings may affect the accuracy of the information.