Age - child settlement application

Hi
Need some classification re the age of child for out of country settlement application.
If a child submits her application at the age of 17. In case application is rejected and appeal is lodged. At the time of decision of the appeal the child turns 19 years.
What age the home office will conversed the child? i.e., 17 ( was at the time of application) or 19 ( was at the time of appeal decision)?
Thank you for your help.