This is already answered in this forum post.
Just use the java action as described in the post that is pass in $ChildDOB/DateOfBirth in datetime input, CurrentDateTime in compare date input and set the return value as Age. Then, add exclusive split with expression to check $Age > 4 and $Age <14 and handle true false paths according to your requirements.
Hope this helps!
sir...see this..it comes error
after..its also error