I got an IQ of 133 on this culture fair test, is it valid?

While that's one of the better online tests, it's still not a real IQ test. You can only take a real IQ test from a licensed psychologist. MENSA gives one, but tends to overestimate scores a bit - they want you to join and pay them money, after all. Not sure why you'd want to join MENSA - it's basically where people who have high IQs but never did anything with it go. Those who did something with it don't need a membership to look smart.