Jessica Alba is getting honest about how quickly her kids are growing up. 

The L.A.'s Finest actress—who shares daughters Honor, 14, and Haven, 11, and son Hayes, 4, with husband Cash Warren—marveled at how time has flown by when she recently sent her two oldest kids back to school. On Sept. 1, the 41-year-old posted several snaps of Honor and Haven sharing a sisterly moment before heading to their first day of classes, jokingly lamenting at how they weren't so little anymore.