Why does 10代 mean Teenagers?

Was reading an article with the heading 'TikTok、10代のための新しい安全な機能', and it occured to me that I have no idea why Teenagers are referred to as 10代.

I get that the literal translation is '10th generation', (like, ９代 would be 9th generation), but what's the reasoning or etymology behind this? Is a 10 year old historically considered a teenager? Searching for this turned up nothing but circular logic, so I'd appreciate if anyone could tell me more, thank you!