Tim McGraw and Faith Hill are officially on the downhill slide of parenthood as their youngest daughter, Audrey, has turned the big one-six.

Audrey celebrated her sweet sixteent  on Wednesday, with mom Faith Hill sharing a sweet birthday message.

“This angel of ours is 16 years old today,” Hill posted on Instagram, with a pair of pictures of Audrey, one of three daughters she has with fellow country music star Tim McGraw.

“Again, it is hard to fathom how quickly the years pass. It is an absolute joy to be the mother of this child,” Hill added. “The most forgiving, honest, joyful human being. And those hugs. Happy Birthday, Audrey!”

Tim and Faith's other two daughters are already out of the house and both are currently away at college.