Board Thread:Naruto Discussions/@comment-36643127-20180819154205/@comment-25122992-20180819154650

Kaguya ate the God Tree's chakra fruit as a whole, while usually Ootsutsuki clan members (like Momoshiki) proceed to harvest this fruit and turn it into pills to consume them afterwards. Both the fruit as a whole and pills grant Ootsutsuki chakra, so Kaguya obviously wasn't the first of her clan to wield it, she just achieved it by untraditional means.