I feel the same way the thread-owner does - I'm in high school aswell, and i really want to get a PhD in math. If i may give you an advice - NEVER TAKE AN IQ TEST!
I have taken an IQ test, and being farely certain i could achieve something in math before the test, i now doubt in my abilities, due to a rather low score. I got 130, which isn't low but not much from a top mathematicians perspective. Many have tried to convince me that IQ means nothing, but it's hard to believe, since these advices often come from very intelligent people themselves, so it's easy for them to say :)
My advice for you is go for it! If you really want it, you can do it. Never take an IQ test, since it won't make a difference in whether you can complete a PhD if you know your IQ. On the other hand, the result may actually - just as me - discourage you and decrease your chances of getting your PhD. So don't go into the IQ trap lol .. :) Just keep doing math because of the enjoyment you get from doing it, and it will eventually come.
Best of luck from denmark