This is part 32 of my 100% Super Mario 3D World Walkthrough. This part includes World Mushroom levels 1 through 3. Below are the times for the green stars and stamp in this stage.
00:04 - World Mushroom-1 - 'Night Falls on Really Rolling Hills' 00:48 - Green Star #1 01:30 - Green Star #2 01:33 - Green Star #2 03:10 - World Mushroom-2 - 'Spiky Mount Beanpole' 04:07 - Green Star #1 04:18 - Green Star #2 05:50 - Green Star #3 06:57 - World Mushroom-3 - 'Deep Black Jungle Drift' 07:33 - Green Star #1 08:35 - Green Star #2 08:54 - Green Star #3