She said >"I was given to Pink Diamond just a few thousand years before she was given the Earth"
She didn't say anything about having belonged to someone else before that.
Gifts can be custom made for the recipient, and indeed often are.
Pearls specifically are made-to-order status symbols, and our Pearl obviously is made to imitate Pink, in coloring and outfit, even though she's not monochrome like all the other diamond's pearls are. But maybe it's intentional, she's supposed to remind Pink of all of her older sisters. I think Pearl was made for Pink, but as a gift.>>101893630
CG Pearl's skin color seems to vary from shot to shot, but most often she's not paperwhite like WP was, but has a very slight peachy hue to her skin. In >>101893482
for example you can see a difference between the whites of her eyes and skintone, and her skintone isn't that different from Yellow pearl.
Indeed, Every other diamond Pearl has strictly the color scheme of their owner.
CG Pearl is the only one who even when they're Pink Diamond's pearl and everything is still as it should be, has a multicolor color scheme, even though pink is the most prominent color.
My theory is that it's because she was given to PD from her sisters to sort of nanny her, be sensible, and also to keep her happy, so she's a constant reminder of the other Diamonds (and their expectations) at her side. She does try to control Pink's behavior and keep her out of trouble, even though she does it in a respectful way.