Thats what teenagers do i did the same it was fun but when she wants something i.e to go to a party and you won't let her go cause u dont trust her she will soon learn from her mistakes and try to be more truthfull this might not happen until shes 20 or so like me
My step daughter does it all the time, even though it is so obvious she's lying, it drives me demented but i try to let it go over my head now unless i feel its something serious.