User blog comment:Leek0421/The strongest Female Fairy Tail wizard/@comment-25324252-20150512003642/@comment-1839664-20150512055813

Mashima stated on his twitter on where Cana stands in the (former) guild:
 * Correct. Plot-wise, she's (Cana's) the third/fourth strongest female member of the guild.  It goes without saying which two hold the top two spots.