Socialize with the kids at same ages

Hai, i had a daughter currently about 2y and half. Most i curious about she usually reject or crying/become crancky when she need to play with her cousin at the same ages. She mostly liked to play or interact with an adult. Is it ok for this situation i had? I afraid that she cant adapt the environment if in future she had to be in kindergarten. Fyi, my daughter is the 1st granddaughter in my family since i was the eldest children. So she also sit with her grandmother since baby until now. Can i get some opinion or solution out there? Tq.