For everyone who is right handed and trying to teach a left handed person something try sitting directly across from them. If they are looking straight ahead at you, while teaching them to tie their shoes for example, they can exactly mirror your movements which can make it a lot simpler to learn.
I'm a lefty and sometimes trying to learn how to do something like that while simultaneously reversing the movements in your head can be really confusing.
DD9 (only 6 days left of her first decade, I feel old) but she does still believe in Santa Clause. Two Christmases ago I decided to stop trying to work to keep her from finding out, I would just do whatever DD5 needed to keep HER believing and if DD9 found out, oh well. I thought for sure she would figure it out this year. We got the kids an air hockey table for Christmas and that was their gift from Santa. There was a bit of a comedy of errors regarding picking up the table and finding a place to store it where they wouldn't see it before Christmas and it ended up being in my SIL's car for a few days where my DN12 saw it and at the family Christmas party a few days after Christmas commented that the table hadn't come from Santa because it was in their car for a few days. I thought that was it as DD9 commented that the table wasn't from Santa because DN12 said it was in her car. She never did put two and two together though.
She knows the Disney characters and such aren't real, knows TV, movie, and book characters aren't real but still buys the Santa and Toothfairy lines.
Her biological father once told me he believed in Santa until he was 15 but he was not the brightest bulb in the tanning bed. I would think in the next year or two one of her friends at school will tell her or someone will start teasing her about it.