Guardian Goddess in Manhattan.
Book 3 in 18 parts, By FinalStand. Listen to the ► Podcast at Explicit Novels.

"Our
Princess grew up around a woman whose keen intellect we rely on to
protect us from unseen enemies," Saint Marie's voice became deeper and
more threatening. "At the age of ten, she," Saint Marie looked my way as
my hand shot up mimicking Aya's identical plea for attention.
"Yes Ishara?" Saint Marie chose to acknowledge me.
"She's nine."
"Fine. At the age of nine, she earned an honorific, Mamētu me eda, which I didn't accomplish until my 19th year." 'Yes Ladies, I'm an epic bad-ass and I've been out-performed by a child'.