Do a standover test. If you don't have at least 1 to 2 inches between you and the top tube when standing flat footed in your regular shoes, it's too tall. You can sometimes get along just fine with a shorter bike depending on frame geometry and personal preference, but too tall is most often a problem.
There is a lot more to fit than standover height, but if it fails that test, you don't have to go any further.