It’s been months since Britney Spears shared a photo of her teenage sons. And when she did on Monday, it was clear how much 14-year-old Jayden James and 15-year-old Sean Preston have grown.

On her Instagram, Spears posted a pair of shots featuring her and the boys standing under a pretty sky. 

“It’s so crazy how time flies,” the 39-year-old pop star opened her caption. “My boys are so big now.”

In the post, Spears explained why she hasn’t shared a shot of her boys in a while. She last posted about her boys in September in celebration of their birthdays. 

“I know … I know … it’s very hard for any mama especially a mama with boys seeing them grow up so fast!!!! Talk about enough to make you go to your knees … Geez,” she wrote. “I’m extremely lucky because my two babies are such gentleman and so kind that I must have done something right… I haven’t posted pictures of them for some time cause they’re at the age where they want to express their own identities and I totally get it.”

Spears’ post comes a month after the New York Times Presents docuseries episode “Framing Britney Spears” premiered on Hulu and FX, looking at her father’s legal conservatorship that she’s been under since 2008. Since the episode premiered, Justin Timberlake, whose treatment of Spears was touched on, apologized to her and said he “failed.”