I can sympathize being more comfortable riding on my tie side as well. Sounds like she is just afraid of picking up speed and is leaning back. She'll need to get over this fear and put her weight over her front foot. She'll have more control this way. It will come with time as she gets more confident with handling speed.
I'm not quite sure what you're asking regarding her stance. Are you unsure of whether or not she rides regular (left foot forward) or goofy (right foot forward)? If so, the test that makes the most sense to me is have her slide across a hardwood/tile floor with her socks on. The way she faces when sliding with her sock should be the way she rides on a snowboard.
Yes, I think you are right there saying she might be scared. I saw a patern yesterday and when she knows how to do something, she gets in line first, then when its time for something she is scared she is last one in line. The hill where they practice seems a bit intimidating even for an adult (me) lol... and they only had one day (half a lesson) on bunny hill... (I think they still consider that top hill "bunny hill") trust me, it does not look like a bunny hill. So, this might be where her fear set in, she basically only had half a class to learn to come down that big hill...I am sure she will get better with time, I just want to inform myself and to be able to know where to encourage her and teach her right way, instead of guessing. So thank you again..
I will most def. ask her to slide on the floor just to make sure.