Do you get along well with your cousins? ! I'm not in good shape.

Many strangers can make friends, let alone cousins. In fact, people can basically make friends, but only in depth. Your relationship with your cousins is so bad that you have analyzed it yourself, so I won't explain it here.

If you want to make a difference, you have to start with the usual greetings, keep in touch frequently, get together occasionally and find a common ground. People don't have only one side, there is always one side you can talk to.