write a new story for yourself

She obviously doesn't regret killing Max because she saved her sons and countless lives by freeing Santa Carla from vampires, but she definitely sees how lost the former vampires are in the aftermath of becoming human again and feels sort of responsible for that. The Lost Boys don't really have anywhere to go since sleeping upside down in an abandoned factory isn't really an option now that they're human, so Lucy opens the Emerson house up to them while they're relearning how to be alive again.

I headcanon that Dwayne and Paul were turned at around the same time and that they're both relatively close in age to Lucy, so I think they're the first of the Lost Boys to come around to her and befriend her. Marko follows suit, and Lucy definitely takes on a sort of maternal role (because even though Max was doing it the wrong way and for the wrong reasons, they definitely need someone to help nurture and guide them).

David decides that he doesn't like Lucy before he even meets her because he has an automatic hatred for any woman Max tries to make into a mother for the Lost Boys. He also absolutely resents her for killing Max because he hates being human again and also, as much as he hates Max, I think he had a hope somewhere deep down that one day he and Max might reconcile and that Max would learn to accept him as he is, and with him dead that will never happen. David doesn't join the other Lost Boys at the Emerson house and instead takes to breaking into Max's now-empty house and crashing there (also I think that after, like, 70 years with Max, he's incapable of understanding that someone could ever want to be a parental figure for a reason that isn't manipulative and controlling, but he's not ready to address that about himself).