Act Your Age is part of the 30th episode with Loose Change that aired on September 20, 2002.
Sylvester, Bugs and Daffy all try to hog attention for Granny. This serves to irritate not only Granny, but also Lola and Tweety. To sort this out, Granny treats the three like they're younger than the others, prompting them to change.
At the house, Granny is impressed with Sylvester feeding himself, but then Tweety accidentally spills his milk. She helps clean the mess, but Sylvester begins to show jealousy and thinks he did that intentionally. Soon after, Bugs, Daffy and Sylvester begin to hog Granny's attention away. This serves to annoy Lola as she thinks they're just being immature for their age and Tweety, who just asked for assistance. This isn't helped by Taz.
Later on preparing for bed, Bugs, Daffy and Sylvester continue their competition for Granny's attentions, while annoying each other. Taz is given a choice of story, but his original choice was read too much so he looked inside hard and found "Termites Terrace". When Granny attempts to read the story, the boys continues their competition. By the time morning comes, Granny is too annoyed in dealing with the wants and needs of the three boys and decides it's time to teach them a lesson.
At breakfast, Granny gives cereal to Lola, Taz and Tweety. Tweety impresses her by eating at the table like the big kids and enjoys the boys favorite cereal. Granny then turns her attention to Bugs, Sylvester and Daffy who are sitting on high chairs and produces prune flavored baby food. Bugs asks Granny why she isn't give him and the other boys their cereal. She insists that the baby food is a much better choice for those who can't feed themselves. They're forced to eat it in disgust, while Taz, Lola and Tweety enjoy cereal.
Bugs cracks and gives up being a baby after missing out in racing with Lola and the other kids. Soon after Daffy and Sylvester start to crack under it after seeing the four playing outside. Daffy asks Granny if he can assist helping Bugs and the other to pick up toys. Granny is impress, but asks him to help set the table instead. Daffy happily accepts the responsibility. Finally, Sylvester cracks when he is seen being carried to lunch. Missing his place, he decides he's finally done with being a baby.