You should not find the groundschool or exams particularly difficult. There is maths, geometry, angles, vectors etc, but nothing too advanced. There is an enormous amount of information to process and facts to remember though, and you will need to spend each evening going over what you learned that day.
Practise questions, and give yourself regular practise tests. For this reason, if you are unsure about exams, I would find a good ground school rather than trying to do it all yourself from books, or ad-hoc. A good ground-school instructor(s) will explain the important principles you need to learn in every subject.
The other thing is with your age you need an advantage when it comes to job interviews, up against all the 20-somethings. When I did my ATPL course, the airlines were only interested in students who had done a CAP 509 integrated full-time ATPL course at a recognised school. Having your licence from such a school might give you an advantage over someone who has spent 3-4 years struggling to complete via the modular route, and flying at weekends etc. The modular route does not necessarily have the same standards, consistency or depth of knowledge. "Chalk and talk" in a classroom is very valuable, and at the school I went to, there were components of aircraft one could look at, hold and examine, to help one's understanding.
Re airline pilot, the job: Be prepared for a few years of very hard work, very busy rosters, night flying, four or six sector days, 30 minute turn-arounds, minimum rest, working weekends, Bank holidays, and at Christmas. 6 days on 2 off was not uncommon, and you became a zombie - you were either working, driving to/from work, or sleeping. You will often have to wake up at 0300 or not get to bed until 0300.
Unlikely to get a long-haul job straight away - those are the top jobs and you cannot just walk into them. You will have to spend a few years doing all the drudgery, (as above) to 'earn' your place. Long-haul lay-overs used to be a few days, (sometimes a week), but are more often 24 hour "bullets" now i.e. fly, eat, sleep, maybe a couple of hours to yourself the next day, then get ready and fly home - often flying all night to arrive when the airport opens in the morning.
Again, I am not trying to put you off, but there is A LOT of hard work ahead; both at flight school and in your first job.
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