Dizzy (Amy Lucas) was the main tritagonist, but was replaced by her son Sin.

Dizzy was frozen in time by Ky, but thankfully has returned! 

I'd go for a gentle motherly voice, but nothing too old, I did a more mature take and it was a bit too boyish due to switching between characters.

My take was really similar to Amy's, but hers was more girly. Please try to sound like a girly, but mature teen!