Yes, so far all the blocks have been 12" and, even if someone picked a star that awas a different size I am sure we could figure out how to resize it to 12".
If you go to this link, you will find everything you need for all the stars. And each month the information for that star will be added to the page:
http://www.quiltingboard.com/user_page.jsp?upnum=2000
Hope you join us.