"Dannielynn is such a great kid and she makes me so proud every day," the actor tells PEOPLE. "I can't believe she is old enough to drive! It seems like yesterday I was pushing her in a toy car!"
The proud father also shared an emotional note to Dannielynn through Instagram along with an image collage of Dannielynn throughout the years.
"Sixteen years ago my beautiful baby was born. That's if you want to feel really old," he laughed. "Many people thought the odds were stacked against you,
but maybe that was geared more towards me than you. Through tragedy, turmoil, and a couple of baby tantrums-today you shine bright and are so accomplished. So proud to be your Dad!"
"She shot back in true Dannielynn style ... 'How do you know you weren't even there?' Ouch," the actor said. "I told her 'maybe not, but I have been there every day since I brought you home.' "
"It's been a wild ride and Dannielynn has brought joy and laughter to my life. Stay off your local roads because Dannielynn is 16! Happy Birthday Rock on Mom is looking down!