Maci Bookout's three-year-old son, Bentley, has conquered another major milestone: Preschool! Well . . . sort of.

On Tuesday's episode of MTV's Teen Mom, Bookout and her then-boyfriend Kyle King (they split in January 2012) take her son to visit a local preschool to consider enrolling, but the visit doesn't exactly turn out as planned.

Leaving Bentley to play with the other preschoolers during snack time, Bookout, 20, is second guessing their visit as soon as he bursts into tears and begins to wail once she's out of sight. "Oh no, this is a terrible idea!" Bookout tells King when she sees her agitated son.

Though mom -- and Bentley -- have since adjusted to being apart while he's at preschool, Bookout tells Us Weekly parting ways for kindergarten in 2013 will be another challenge. "I'm dreading when Bentley goes to kindergarten. I'm used to it being me and him," she explains. "I'm going to be like, 'Where is my friend?'"

Watch more of Bentley's emotional first preschool visit in the clip above before Teen Mom airs Tuesday at 10 p.m. (EST) on MTV.