Cousin suddenly sent a text message saying that she likes cousin.

Cousin is more rational, knows that you can't do it, and doesn't want to harm you. Marriage between close relatives will affect future generations. My cousin's family won't agree, and neither will yours. Feelings that are not allowed by elders will not be happy. Actually, you are fine now. Just treat him as a cousin or a good friend, and keep a proper distance. You can live forever, but it is not good to be too close. If you like my cousin, you should think of him and let him find the right person, otherwise you will hate him in the future.