Can you believe your baby is already 3 months old? Seems like only yesterday she was a newborn sleeping 16 hours a day. She’s well past the coos and gurgles of months 1 and 2. She’s now a “big girl” smiling, giggling, discovering her hands and becoming more social by the day. 3 months old is a common age for parents to start wondering about normal sleep patterns and how to avoid (or fix) sleep problems.