Gomez and Bieber have dated on and off since 2010, most recently splitting in March.
"Selena is definitely on a different path right now and in a much better place since Justin is out of the picture. Mentally, she is done with him," the insider continues. "She isn't focused on dating as much as she's just really focusing on herself. She's happy right now just spending time with her girlfriends and going to church."
Another source also adds that Gomez is putting her relationship with Bieber "in the past." And while she was "very shocked" to hear about the engagement, she ultimately "doesn't care."
"Selena knows that Justin makes rash decisions, but wishes them both the best," the second source tells E! News. "She is truly focused on herself and Justin is no longer a topic of conversation in her life."