Nostalrius Begins - Quality wow vanilla realm (1.12)

Hi, I have a question. I have created an account on the site (https://en.nostalrius.org/register) with a name (20 characters = max possible) but when I try to login in the game the max characters in the username is 16.

That's weird and I now I can just create another account with less characters but I would love to know if it's something I'm doing wrong or is it normal and everyone (except me) already know about that. I would prefer to change the username (I don't know if I can/how) than creating another one because I wanted that email I registered.

Please help, thanks in advance

I can only use up to 16 characters in the username also, I'm not exactly sure why it is set to 20 max but it might just have been a temp number that was never changed.

Man, that s*cks. Now I already created the account with my email... Can I change the name, or the email, or delete the account to create it again with another name? I really wanna use that email and only have one account.