Will Apple tell me if law enforcement has ever access my account?

Visit https://www.apple.com/legal/privacy/law-enforcement-guidelines-us.pdf to learn more about the guidelines. Apple will notify you unless restricted by law. (Section II-G)

No. If law enforcement makes a legal request for data from any online service provider, the provider will not inform you of that request. No company can inform a user if law enforcement is investigating someone or accessing someone’s data. That is not how warrants work.

You would only ever know about it if the investigating agency contacts you about it, or charges are filed.