If you recently obtained a new degree include the date to show that it is current but then be consistent and include dates for each degree.
Ageism will happen. It is unavoidable. People will judge you based on your years of experience, what you look like, and even potentially your email address. It is illegal but almost impossible to prove.
There will come a point in your career when your experience will outweigh your education. When that point comes you can consider removing your graduation dates.