User blog comment:Zathronas/Speculative author: Who is Summer Rose?/@comment-5217560-20140809062848/@comment-10380701-20140810025826

Well, age isn't really a factor if we consider that both of them may be prodigies in the fields of Dust/Semblance sorcery.

I presume Glynda may be at least around Summer's age. She gives off a more adult vibe than Cinder for me.