Is it true that the PPL course is very difficult?
do you need lots of maths and high levels of complicated math? And have to be very intelligent?

Required math skill is very minimal. Simple addition, subtraction, multiplication, division, etc. Some quick mental calculations are sometimes necessary, but nothing too complicated. You do not have to be supremely intelligent to get your PPL, but you do have to be dedicated and study hard. There is a lot of material that is completely foreign to most people that takes a lot of work to fully absorb.

the early pilots had common sense and guts to fly and they did it,,,,

if you like it you can make it...

currently l am doing my PPL for fun..

Yes, getting ur PPL is hard work. There will be times where u get frustrated with a maneuver & feel like flying is not for you. There certainly were for me. However, l can guarantee u will also have some of the most fun you've ever had in ur life. My first solo was an experience l will never forget. That & the cool factor when u take ur friends up & impress them with the view does not hurt either. Commanding an aircraft & logging coveted Pilot-in-command time is an achievement that less than one percent of the entire US population can lay claim to, & this statistic is true pretty much anywhere else in the world.

If u can do basic arithmetic, adding, subtracting, multiplying & dividing. You can fly an airplane. You do not have to be a Math genius & u certainly do not need to be a Mensa member. However good judgment is a requirement, as pilot-in-command u r solely responsible for the safety of you, ur passengers, & ur aircraft. And a commitment to keeping yourself current in both knowledge (the FAA is constantly updating the rules) & flight proficiency is also a requirement for safely conducting a flight.

Flying is one of the most rewarding experiences u will ever have. But as with anything rewarding u must put in the work to earn the privilege. Once u do, sit back & enjoy it. It will be worth every minute of it.

Basic maths is just fine for you to get your PPL. One needs more of a presence of mind than intelligence in order to fly. If you pay attention to your instructor and do well in your ground subjects and procedures, you will find out that obtaining your PPL is very easy.

In my experience, there r two types of student pilots, the academics, & those who can manipulate the controls of the aircraft well, i.e. the good stick & rudder pilots. Very rarely will u find someone who excels at both the academic work & the flying training.

For the PPL course, & in fact all the way to ATPL level, the maths is never more complicated than basic triginometry, Sine, Cos & Tan. Furthermore, for the exams u should have a good knowledge of how to change the subject of a given formula. This is taught in schools as basic algebra.
So if u struggle with the above mentioned things u might struggle, but otherwise, no, the maths is not 'high level' at all.
Good luck!

l am learning and l am 16 and its easy so far