Pages running on a Mac

You can use the Finder's Get Info panel (control+click on the document and select Get Info) to check the creation/modification date. Pages provides no document information such as creation date on an opened Pages document. Pages is no Word clone…

You can also examine the metadata of the file which will show the content creation date if the file system date gets altered. I couldn't find any of mine where that was the case, though.

The Preview pane in Finder will show the created date, but doesn't show the content creation date like for images.

You can directly view the metadata using mdls in Terminal:

mdls -attr kMDItemContentCreationDate <path/to/file>

You can copy/paste the part to just before <path/to/file>, leave a space, then drag the file into the Terminal window. Hit return.