Rosalie always wanted a child of her own. She loved it when Bellas baby was born because that meant she could get a bit of the feeling of being a mother, but it didn't last long.

Two vampires can't procreate. So Emmett giving Roaslie that biological baby she always wanted was off the table. And you can't turn a child into a vampire due to the vampire laws, but there's nothing against turning a teenager into a vampire.

That's where you came into play. Rosalie wanted a child, and Emmett got his wife whatever she wanted.

He had picked you out specifically. You were just perfect. His vampire venom turned you and gave you those vampiric traits.

You still had a human family though. A family you were torn from to appease some woman and be used as a gift.

Only a week into this new "family" and Rosalie won't stop smothering you with love. And Emmett kept giving you that fatherly love that you give toddlers.