What should I pay attention to when I meet my uncle's little sister for the first time?

I believe there will still be a distance ~ ~ ~ so close people meet for the first time at this age.

Watch your words and deeds.

Look at her performance before making a choice.

She is indifferent, so it's better not to ask.

She is a warm and cheerful girl ~ I don't think there is anything to ask.

At least ask the wrong questions. She knows you are her family and cares about her.