Being a new parent can be an exhilarating — and challenging — experience.

The seemingly never-ending diaper changes, the3 a.m. feedings, and the fears of doing the wrong thing can take a toll.

So it’s no surprise that when your tiny new human first smiles back at you, those struggles melt away in light of the joy you feel seeing that beaming face.

“All of thosesleepless nightssuddenly feel worth it,” says Dr. Brittany Odom, pediatrician in Orlando, Florida.

Newbornscanactually smile right from birth, but doctors call this a “reflexive” smile, which can be caused by internal factors. You may even notice your infant smiling as they sleep.

“Those early adorable smiles may be due to a variety of other reasons that make your baby happy, like passing stool,passing gas, or just generally being comfortable in your arms,” Odom said.

A true social smile, in which your infant is looking at and reacting to your expression, can happen anywhere from 2 to 3 months of age.

To tell the smiles apart, look for differences between a social and reflexive smile:

  • Does baby look fully engaged?
  • Do their eyes smile along with their mouth?

That’s how you can tell your little is responding to their surroundings — such as their parents or caregivers’ faces — and developing a sense of social awareness.

You may be wondering how to encourage your little one to smile. But you probably just need to continue doing what you’re doing. The recommendations are the same as before they were smiling:

  • talk to them
  • look at them
  • smile at them
  • sing to them
  • play games like peekaboo

All of these things are good for baby’s development and emerging social skills.

Social smiling is not only joyful — it’s also an important part of your little one’s brain development. Baby is learning social cues, and how to get the attention of caregivers. They’ll make more eye contact and show interest in faces.

If your baby isn’t showing you their adorable smiles by 2 months old, there’s no need to worry, Odom says. “Every baby doesn’t follow the textbook, and some take up to 4 months to start smiling socially. Social smiling is a part of her social development, but not the only component.”

If you’re concerned about your baby not smiling, talk with your pediatrician about their development overall.

Smiling is just the beginning. In terms of language development, there are a ton ofwonderful milestonesto look forward to. Babies generally coo, or make sounds, at 6 to 8 weeks, andlaughat 16 weeks.

Then comes the sweet babbling around 6 to 9 months, where babies tend to repeat sounds likebababa. Enjoy these before the emphatic “No!” arrives at 6 to 11 months and becomes a favorite and mainstay in the toddler — and later, teenager — vocabulary.

Whether your baby smiles at exactly 6 weeks or not for several months, it’s important to remember not to panic if your baby isn’t reaching every milestone by the book. “Books provide guidelines only,” says Dr. Melissa Franckowiak, who practices in Buffalo, New York.

Franckowiak says that while development usually occurs from gross motor to fine motor, some babies prefer more fine motor or cognitive activities, or vice versa, so there may be some individual differences.

“Keep in mind that all children develop differently,” she said.

If months go by and you see more than one sign that your sweet babe isn’t engaging with you — such as not making eye contact — make an appointment with your pediatrician.