You and Shelby have become best buddies. For month she kept her respectful distance - I believe you were just too loud for her - but recently I look at you and there's Shelby too, never more than a few feet away. She likes to sniff the food I'm giving you, she plops down on the floor near where you play, and she meows in response to your sweet baby blabber.
Ever since we got your new high-chair, Johnny, Shelby is always sitting next to you. I suspect she might be a bit jealous, but perhaps she thinks she's a baby too, which is even a bigger problem.