Yeah, you can do it from your account settings page. Be aware though that if you delete your account, you'll never be able to get it back, and you'll also not be able to open a new account with the same username in future, IIRC (deleted my former account some time ago and I believe that's the information I was given at the time).
It's better when you rethink it! Don't delete your account, later you'll regret it, because the project is an unique community! Don't do it, a good tip from me! But if you decide to do it, probably you can try it at the setting page of your acc. Rethink it...
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Well if you're sure, check the settings page i'm pretty sure you can close your account there.