Well I got them all first time, and my high school major subjects were art, history and classical studies ...
My wife had no trouble with them either, and she based all her school studies around her teenage ambitions to be a fashion designer
Seriously, all this melodrama about 'what to study before the ATPLs' is highly over rated. If you can add, subtract, multiply and divide then you have all the tools to crack even the most tricky ATPL formulaes you will encounter (i.e. PNR and ETP calcs in ATPL nav for example). Once you've got the notes in hand, or you start attending the classes, then they will teach you all the new skills you need to know. There are of course, some geeks who can seemingly breeze through these things without doing tuppence worth of study and going to the pub every night on ground school, but you'll still be fine even if you learn at the pace of normal mortals, as long as you put the study in before you go to the exams.
The reason people have so much trouble with ATPLs is not the difficulty level of the material, so much as the sheer mind boggling volume of sh!te you have to memorize
Unfortunately that isn't something you can prepare for by studying at school. You just have to take the bull by the horns and start trying to learn this stuff, make little notes and mnemonics and summary sheets of all the chapters as you go, and pray you can remember enough of it under exam conditions to scratch a pass.
And the really stupid thing is, that once it's all over and you're flying those airliners, you will use about 0.00001 % of all that knowledge you learned (in fact you will have forgotten most of it within a fortnight of getting the exam pass). The most challenging mental arithmetic I've had to do in my career as a pilot is when I'm trying to convert the price of two bottles of duty free Absolut from Norwegian kroner to pounds, or maybe how much is a 15% tip on a £76.45 restaurant bill
After a couple of years you will give your ATPL notes and practice exams to your mates, sell your nav wheel on ebay, look back and think 'what the hell was all that about'?