Well done on the first lesson, first small mile stone under your belt and no doubt many more to come!
I took 18 months to do my PPL whilst earning the cash doing bar work, I used to try and have one lesson per week but in reality it was more like once per fortnight by the time the weather has taken it's toll. I still passed on 45.5 hours despite having it spread out, and so I think the key thing is your attitude towards training. If you turn up once a fortnight, expect your instructor to tell you all you need to know and then finish your lesson and head to the pub, you're going to struggle to pass anywhere near the minimum hours. The key thing is to make sure you have all the PPL training books, and after each lesson ask your instructor what's coming up next. Read all about it, do some further online research in to particular subjects if necessary, and don't forget to think through your previous lesson in your head to ensure that you remember what you were taught. If anything didn't make sense, go look it up.
Once you've passed, you need to combine ATPL theory exams with hour building (you need 150 hours total time and to have passed all 14 ATPL subjects before commencing CPL training). Hour building options are fairly limited, I joined a private flying group which offered roughly the same rates as the flying schools but much nicer aircraft (I flew an auto-pilot equipped C172 for what the flying school charge for a C152). Some people go to the US for hour building, but you can find plenty more information about that on here. If you're going modular then most people study for their ATPL exams by Distance Learning through a ground school such as Bristol GS, or a cheaper alternative currently is CATS Aviation. The ATPL's are hard work, despite what some may say. Yes it is possible to pass the ATPL exams by hammering the question bank over and over, but it's not going to look very good when it comes to an airline interview one day and they ask you a technical question to which you don't have a clue how to reach the answer. Best tip, if you're going to study for the ATPL's then make the most of your time and do them properly, after all you are paying for it so you might as well make them count and learn the stuff as best as you can.