   :
Create FUNCTION Age (@DOB DateTime, @CurDT DateTime)
RETURNS TinyInt
As
Begin
Declare @Age SmallInt
Set @Age = Year(@CurDT) - Year(@DOB) -
Case When Month(@CurDT) < Month(@DOB) Then 1
When Month(@CurDT) > Month(@DOB) Then 0
When Day(@CurDT) < Day(@DOB) Then 1
Else 0 End
Return @Age
End

    :
select firstbame from Family where Age(Birth_Date,getdate()) between 16 and 24 