Majah is the Mother of Aqua, both of them are Nymphicotes which are a subspecies of the Nymph race. although you'd never know it based on how they present themselves and their powers. she's an incredibly powerful and aged Nympicote, so she's got an entire arsenal of magic weapons/spells/items at her disposal. She's of divine origin so a lot of her power has holy essence imbued in it, but she's not exactly a saint. she's extremely flirtatious, sassy, and witty, she likes teasing and making fun of others. she does have a bit of a temper at times but you'd have to really annoy her to see it. She is one of the many characters which do Die during the series, but that doesn't mean she leaves the series. she appears every now and again as a spirit or ethereal form. her power and body however were reincarnated and given new form which gave birth to Aqua. who will overtime learn and acquire all the power her mother previously had. Majah is pronounced My-yah which is weird I know but it's how it's pronounced.
I imagine Majah's voice to be around young adult age. she's extremely flirtatious and sassy so the younger voice fits much more than one that would be acquainted with her age.