It is possible that, certainly by what is now called Middle School, I fell into the "fixed mindset"--I couldn't do math, never would do math, and that was that. It was so ingrained in me that I almost flunked statistics courses at BCIT when--In hindsight--I should have seen how important the lessons could be in my future career.  But...was too young and, well, "set in my ways."
However...
About 12 years later, I established my own company. Had plenty of skills, but I became convinced that math skills were the key to my financial success. None of my other skills mattered, if I couldn't master math. If I didn't master math, my business would fail and I would starve.  I got really good at basic math. REALLY good. 

So, I have an educational theory, called WIIFM, short form for "What's In It For Me?"