How long do I have the Twitch account?

Someone said he knows that I've had the account since 2018 and it's just right… How can I see it and make it private? The guy was a streamer

You can see it when you write a message in the chat and then click on your name or stop at others. Then you can see when you have registered, when you follow the channel, etc. You can't exhibit that as far as I know.