I love 3-month-olds because their personalities finally come to life! Here are posts focusing on Montessori 3-month-olds.
Montessori Baby - Preparing Yourself for Month 3
Montessori Environment at 3-Months-Old
Montessori Friendly Infant Shelves to Love
What Should My Child's Montessori Floor Bed Look Like?
How We've Used a Sheepskin
What Should My Child's Montessori Floor Bed Look Like?
How We've Used a Sheepskin
Montessori Activities for 3-Month-Olds
The Butterflies Mobile
Batting