MENSA IQ tests can be given at any age. Back in the day, most of us took one in the 10th grade to see if we qualified for membership in the school MENSA club for high school. They can be administered in elementary school, too with age-appropriate examples in their questions. It's mainly a test of the ability to 'figure things out', comprehension and logic which would obviously then contain sections in the test involving grammar, graphics and math. Once an IQ has been established, it does not change. It has nothing to do with education and degrees...the score is basically what you are born with. Again, it's about ability. Most people score at different levels in each section of the test. Also, each test is timed. When the test giver says, "Time's up" you're done no matter what point of the test you're at. So, speed factors in as well.
My score was 141.