That's pure fiction. There's not much motor control in a newborn. This has actually been depicted in some isekai series where the MC is frustrated because they can't do anything for a long time after being born. At least listening to sounds works.
@Kaarme i counter that with most isekai characters are teens to young adults i consider it plausible an old person that "has" experience using weak limbs that don't exactly function as wanted might be able to pilot an infant body.
@aberdeus Yes, I agree she would to quite a shocking amount (relatively speaking), and especially she would develop a lot faster simply by having a reasonable mind behind the actions. However, I'm not sure the structures simply are yet there so early. Wouldn't she still be like a car without wheels? Just like she simply can't talk yet because the body isn't ready for it even if the mind is. A newborn baby can't even support its own head.