Unable to learn Expert Tailoring at any tailoring masters

Hi there,

I'm leveling tailoring on my new mage, currently at 150/150 and unfortunately I can't find any tailoring master with Expert Tailoring available. I've tried the masters at Ogrimmar, Thunderbluff, Shattrath and Dalaran. Nothing available from any of them. I'm level 18 but I've been told that doesn't affect professions, unsure now whether or not that's true and if that's the issue.

So please let me know what can be done to fix this, thank you. :D