Meg Donnelly was 16 in Disney Parks Presents a Disney Channel Holiday Celebration when she played the character 'Herself'.
That was over 6 years ago in 2017.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 23, and has starred in 12 movies in total, 11 of those since Disney Parks Presents a Disney Channel Holiday Celebration was released.
In Disney Parks Presents a Disney Channel Holiday Celebration, I think Meg Donnelly looks: