Enabling pages

Site URL: http://www.artworksexcelsior.com/

I have a number of pages created under a heading category (art materials). Two are enabled but when I try to enable another I get a message that the maximum number of enabled pages has been reached. Only two pages can be enabled? Really? What's going on here?

You have to add all the pages  that are enabled  together, depending on how old your site is and  if you are on a personal plan the total number of active pages is 20, and that number  is determined by any separate pages under config/ pages including index pages. Folders and links in a folder, blogs posts,  are not part of that number.  My personal site is five years old and I have the 20 page limit to deal with as well. 

I'm on a personal plan as well and my site is about 3 and a half years old. If I upgrade to a business account (which I should do anyway) will that fix the issue? 

A business plan will have unlimited page count and custom page coding. You can also start a new personal plan as well, that will make the page count unlimited, but it does not allow custom page coding, which yours and my older personal plan allows. It is a trade off in  other words.