I think it was e biggest of its cousins in First Contact but still smaller than the Enterprise-E. I think it was more on par with the Ambassador or Nebula with regard to length.
As with all things, Ex Astris has an article
about it with size comparison charts. It is in kind of a gray area.
As for it being a carrier, yes it does have what appears to be landing bay doors in back of the saucer and force-field protected launch bay doors in a cut-in at the front of the saucer.