Kindergarten
noun
If 幼稚 is childish, then a garden for childish people would be a place full of lots of children, probably growing in some way. When you're growing little children in a garden, you're putting them into some kind of school. In this case, it's a kindergarten.
ようちえん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Will help to know 幼稚 as well.
幼稚園のクリスマス会のスケジュールをまた微調整しなくちゃいけないかもしれないの。
We might have to make another small adjustment to the kindergarten Christmas party schedule.