My daughter is a December baby and yes she went to school full days when she was 3. I hated it .... She loved it. She was ready (although I don't think any child should be in school full days for jk) she is a social butterfly .... She knew all of her letters upper and lower case she could count to 20, she knew her colors and shapes .... She was ready .... Her school put all the children born at the end of the year in the same class so all the kids were around the same developmental stage..... She is in SK this year and is in french immersion ( halfway French and half English) she is doing great ..... I too am a december baby (Xmas day to be exact) .... I found that I did struggle. So I guess it really depended on the individual child ..... Are they ready ? Emotionally, intellectually? Is she toilet trained ? Can she dress herself ? Can she hold a pencil/crayon properly, does she hold a book upright ( instead of upside down) can she communicate fairly clearly, can she describe basic feelings and emotions, can she follow simple directions, does she play with other children and take turns, those are some things that will tell you if she is ready .... However some kids don't show these skills but learn them at school