MGM Resorts currently has page after page of job openings.
Click on this link: http://www.mgmresortscareers.com/#
go to the JOB SEARCH (center of page on right), select a property and click on "GO"
Once you have opened a basic page, click on "Job Search" from the menu on the left and you can control by property and job type in your search. The specific job description should include age expectations.