How long has my Twitch account existed?

Can I see how long my account has existed?

In a pinch, you can check your emails to see when you received the confirmation email for registration. Surely you will have received one.

Not at all, why should Twitch offer this feature? OO

Click on your name in the chat, a small window will open. There you will find your information on how long you are a follower / subscriber at xxx. Below you will find your general information and your registration date.