Jessica Simpson shared an Instagram picture of son Ace, 14 months, eating a messy snack while walking on Thursday, Sept. 18 Credit: Courtesy of Jessica Simpson

Bed hair, don't care! Jessica Simpson's adorable son Ace is growing up — and fast! His famous mom shared a new picture of him (and his unkempt hair!) via Instagram on Thursday, Sept. 18.

Ace, 14 months, looked like something had caught his eye while he walked barefoot on the family's wooden floors. He held onto a snack with crumbs adorably left on his pouty lips.

Simpson, 34, has rarely posted snapshots of her son standing on his own two feet — a milestone she's sure to be treasuring. That same day, the fashion mogul said she and husband Eric Johnson probably won't be giving Ace and 2-year-old daughter Maxwell any more siblings.

"Oh, we are done," she said during an interview for On Air With Ryan Seacrest. "I say we're done. [But,] I don't want to accidentally get pregnant one day and then that poor kid feels like it wasn't meant to be or something. We've got the girl and we've got the boy."