I can't really say as I am on a waiting list for the Advanced Skills but wanted to welcome you to the group.
For what it's worth, I do not think taking DBT more then once says anything negative about you. Right now while I am waiting for my DBT I am working through the DBT workbook on my own. I can see where things could be harder to get through. I think it is a good idea for you to be taking the individual DBT then with your parents. More will come out and you can be more open.