New forum software (Discourse) has something called Trust Levels. You are limited in your ability to post links, except to certain sites Blizzard approved, until you reach a higher Trust Level. See New Forum Guide - Syntax and Features - #132 by Amine-blackwater-raiders for details.
What you can do to post the text of a link without it trying to convert it to a link is use tick marks (found to the left of the 1 on a keyboard) around the link:
strawpoll.com/8kk72xw8
That doesn’t make it a link, but also lets you post.
Personally I’m playing warlock first, because it will allow me a smoother initial leveling experience. Warrior can come later when I have the warlock able to support him.