By the end of this book reaches college levels. There's nothing better to show how interesting mathematics, to look at it with wonderment. Our education system is to blame.

https://www.amazon.com/Playing-Infinity-Mathematical-Explora...

I'd very strongly recommend https://en.wikipedia.org/wiki/How_to_Solve_It to familiarize yourself with some fundamental processes and https://www.amazon.co.uk/Playing-Infinity-Mathematical-Explo... before you lose yourself in a highly symbolic and abstract world, appreciate the beauty of it first, it'll make the long journey much easier.