Here is the full list of all 18 Grow Up achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Discover the bull and the sheep
Blast a Critter 100m
Complete a challenge holding a Critter
Take a Critter to the moon
Discover letter block P
Collect all crystals
Complete the game 100%
Complete all challenges
Unlock all Telerouters
Throw 100 seeds whilst gliding
Unlock all seeds
Ride two Sporchids simultaneously for 400m
Plant 10 Champolines on top of each other
Orbit the entire planet in BALL mode
Flower all STARPLANTS
Rescue MOM
Bounce on a Youch 7 times without touching the ground
Visit all biomes