How old is Rosie McClelland?

Rosie McClelland is 10 years old (born September 7, 2006).

Rosie was 5 when she and her cousin Sophia Grace Brownlee made the video "Big Bass" (2011).
Sophia Grace was 11 and Rosie was 7 at the release of "Sophia Grace & Rosie's Royal Adventure" (May 2014).