Macy Bookout posted a sweet picture of herself with son Bentley on Saturday, July 6. Credit: Courtesy of Maci Bookout

My, how fast they grow! Teen Mom star Maci Bookout posted an adorable picture of herself with her 4-year-old son, Bentley, on her Instagram page Saturday, July 6, looking happy as ever.

In the sweet snapshot, the 21-year-old is seen holding Bentley, (whom she shares custody with ex Ryan Edwards, 25), while the tot has his arms wrapped tightly around the MTV star's shoulders. "Bookout cookout with my best buddy!" the Chattanooga, Tenn., native captioned the picture.

Bookout, who's currently dating fellow motocrosser Taylor McKinney, proudly raved about her son to Us Weekly back in November.

"He gets gold stars every day. I'm so proud of him," she boasted of Bentley's time in preschool. "They always write comments on why they get gold stars and normally it's because he'll clean up without being asked or follows all the rules."

Bookout, along with Bentley and Edwards, appeared on Teen Mom from 2009 to 2012.