Training to be a pilot is difficult, otherwise everyone would do it.
Seriously though, there is a lot of groundschool to cover on the course, but the actual technical level of this work is not too hard (somewhere around A-Level standard for the most part).
Maths and Physics come in handy for the more technical bits, bt generally it's an exercise in learning a lot of facts.
If you get stuck with bits there are always people on PPRUNE to ask for help.