are there different iq tests for different ages?
Yes. E.g. one of the most widely used intelligence tests is the Wechsler scale. There is a WPPSI (for very y0ung children), a WISC (age 5 to 18, I believe) and the WAIS (for adults). ... Take the time factor out of IQ tests and you find people with 30 points difference are practically as smart as each other.