Some characters are hard to explain.

Ming-Ming is introduced as a young idol with a bit of an ego, she's so confident in her abilities, she claims to hold back against opponents especially boys which actually works, but her true self is the pre teen tough girl Ming-Ming which shows her true self dropping the sweet act and acting like an actual beyblader.
As to why I say she's a strange choice for Beyblade is that she brings idol culture into a toy anime along with idol anime tropes right down to her changing her age Sailor Moon style for battle.
Not a bad character per say, she was actually one of only two winners in the BEGA team against the Bladebreakers, this actually makes her the best female blader of the original franchise, mind you the competition isn't exactly big for that crown.