I was 17 years old when I first owned a website, it was image/video uploader that provides embed in HTML, BBCodes and URL for customized profiles and forums or anywhere. Started the first website in '05.
I was 17 and at that time Internet in my country was a rarity and costed more than all utility bills combined, just for a dial-up and couple hundred hour access/month. I built it using MS Frontpage and hosted it on geocities which was Yahoo's free hosting. I still remember the good ole'days of tripod's guestbook service and really simple textual website pages. The world is totally different now, I wish I'd been born 10 years later than I did! LOL. These days kids can make blogs even before they are 10, lucky chaps! But hey, tomorrow perhaps kids will be building their custom robots by 10 and today's kids will think like me.... it never ends, enjoy what you got and make the most of it =)
I was 17 when I started building my website. it was hosted on wordpress and just a subdomain. I manage to earn with that site by selling links and reviews.
12, the site I made on HTML, dial up connection, Netscape Communicator was the most common browser. Now I am 26.
I made my first Wix website at age 10. I am now 12 and know advanced CSS/HTML/PHP and I custom code my websites.