There could be so many factors that determine this and for my kids I feel they seemed eager to socialize and meet new friends.

It doesn't matter how to tell if our kids is ready, there's a age for them to enter kindergarten. Period.

When my kid is always wanting to know more about things and likes to play with other people

When they walk around the house with their backpack and talk to me about school

My child needs more entertainment than I can provide! Haha

When they’re ready to learn more than parents can teach

And when they say they can’t wait to see their friends

Excited to meet friends! But also depends on the child

Eager to go to school, always asking to meet friends

When they start being keen on starting school.