Such is the nature of concrete. It is very porous, and a poor choice for a kitchen countertop.

That’s just concrete. It’s the first of many patina spots. Go ahead and create more, until they all blend. Concrete is just as porous, and etches just as much, and chips just as much, as any marble. Only film forming coatings will prevent that. Then you have a plastic surface that will peel.

Embrace the patina. Years from now when you see the spot wonderful memories of your child being little wil flood back bringing smiles instead of fustration.

Maybe a degreaser for concrete garage floors or driveway would help. Also, might try rubbing cornstarch or other dry powder into it to help absorb/wick up some of the oil. Repeat applications would be needed. After removing the oil spot I would put a good concrete sealer on the counter to prevent future stains from food/cooking. Enough coats of sealer until water will bead up on it instead of being absorbed.

Acetone please.