"Yrreeeeaahhh?" Mary meowls, padding her way over to Jess. She's squirmed her way out of the children's clothes that Jess put her in, as any cat would have.
"What do you think? Now I can be your mommy for real." Jess holds out her arms looking for approval, but a thought strikes her. To get it really right, to make sure nobody recognizes this little cat girl as Mary, she'll have to take her to the beginning. The very beginning.
Jess hops over and grabs the box before Mary can form the words and returns quickly with them. "Okay Mary, you and me are gonna be the perfect family, but we gotta drink from these bottles one more time, are you ready?"
Mary, hesitant, nods her head as Jess takes the youth vial out once more and accepts the drink as Jess tips it into her mouth. Down, down, down Mary goes, until she is at the beginning of infancy, a kitten-girl somewhere between the size of a kitten and a newborn.
Jess takes up the cat and female vials and swallows more of them, pronouncing her cat-like features and more importantly to her at this moment, making her capable of caring for Mary as only a mother can her newborn baby. The two still have humanoid features, but they're barely noticeable and only under intense scrutiny.
Now much smaller than she was before, Jess slips out of her clothes and pads her way over to Mary on all fours.
"There we are, my little baby. Now nobody's going to know the difference."