This isn't how IQ tests work. IQ test results are measured relative to a population. In particular 100 is the mean with a standard deviation of 15. So if you score 115 on an IQ test it doesn't mean anything in a vacuum. It means that relative to the population who took the test you scored better than ~84% of people. An IQ of 130 means you scored better than ~98% of people, and so on.
This is what led to the Flynn Effect [1]. It was the initially extremely surprising observation that raw IQ scores over time were increasing. In other words somebody who scored a 100 in 1970 was actually scoring substantially higher than somebody who scored a 100 just a few decades prior. Not so fun fact: starting sometime around the mid nineties, raw IQ scores started declining, at a substantial rate, in many and potentially all developed nations. In other words somebody who scored a 100 in 1995 is scoring worse than somebody who scored 100 in 1975. The reason for this is unknown and controversial (as all things even potentially genetic nowadays), but the effect persists even when controlling for things such as immigration.