Since you're new, the easiest way for you to check is do you have the Road to 70 buff? The one that gives a boost to experience gain.

If you have that then you're locked to your current world for 90 days. If not, you can move (as long as you meet all the other requirements not listed here).

To answer your second question, when it says 90 days, it means 90 days from character creation.

Hope this helps!