Ah, okay. I think it's probably because you don't have a high enough post count. The admins put in a few restrictions on new accounts to deter bots and spammers.
I'm not sure how old your account has to be before you can edit. You've been here for 10 days, but you only have 3 posts. If you post some more (sorry, not sure how many you need), you'll be able to edit your account. When you can edit, follow the steps I outlined above, and it'll work.
@leif erikson,
@The_J, can you please refresh us on how many days and posts a new member needs for editing their account?