Yes, the rates to vary with age of the child

current maximum rates of FTB A as follows (per child, from Centrelink website):
child 0-12 years is $156.94 p/fortnight,
child 13-15 years is $204.12 p/fortnight
child 16-17 years is $50.12 p/fortnight (depending on circumstances, once child is 16 would transfer to Youth Allowance if eligibile)
child 18-24 years is $67.34 p/fortnight (depending on circumstances, e.g. student status)

current maxiumum rates of FTB B as follows (per family, based on age of youngest child, as per Centrelink website):
child 0-4 years is $133.56 p/fortnight
child 5-15 years (or 16-18 years if child is full time student and not in receipt of Youth allowance) is $93.10 p/fortnight