Unless the photos are of you doing something illegal, like with kids or animals or dead people, you really don’t need to worry.

If they do send the photos, your friends and family are going to be surprised but almost everyone looks at porn (including your parents) so it’s probably nothing they have not seen before.

If it does involve something illegal, you should report the attempted blackmail to police to stop the blackmailer doing something like this to other people, and you would have to accept the consequences of your actions.