Having looked into this for my genealogical society this is what we have found:
If you have any data that can identify a living EU citizen regardless of where they reside or any citizen from any country who resides in the EU then you must comply with the regulations. How this will be enforced outside the EU is not clear.
If you do have such data in any form electronic or written then you must have permission of that person to retain the data. They have the right to ask what data you hold on them and also if they ask you must delete the data. You must only use the data for the express purpose contained within the permission obtained by the person. You must ensure the data is secure and notify the person who gave permission if your security is breached.
There is a lot more to it than that but those are the major points as we understand them.
If you are at all concerned then you should seek professional legal advice.