I tead online that its fine. As long as baby is okay and fine after taking. Its ok to give cold. But if u are worried, maybe you can slowly adjust the temperature. Leave it out for 5 mins and then slowly heat abit from abit cold to room temp. See if she accept.
i've read before that it is ok to serve cold breastmilk :) i used to serve my LO cold breastmilk every now and then. maybe your LO just has a preference. as long as she doesnt shows signs that she is affected bt the cold milk i believe it is fine :)