Sulphate,
Good advice from Redsnail, try and become familiar with the rules and regualtions, it can make dry reading, but is worth a peak.
In a nutshell, you are now old enough to start flying, at 17, you can obtain a PPL (Private Pilot Licence). Now this is from memory, so I hope it is right, you can take your CPL (Commercial Pilot Licence) skill test as long as you are 18 years or older, and you must be 21 to get your ATPL (Airline Transport Pilot Licence) issued. The ATPL is the licence you need to fly as a commander of multi crew aeroplanes. Now, you have probably heard people talk about the ATPL writtem exams. These are the exams you are required to pass, either prior or after reaching the practical experience requirements which 1500 hours total time, again this is broken down into certain criteria.
I would start flying as soon as you can afford it. Whilst I was at college, I worked part time, and saved the cash for the PPL. I took time out, the summer of 1995, and completed the PPL course. After that I still had 2 years of college to complete, therefore I managed to keep current, and on completion of college and no sponsorship from the airlines, I elected to go into full time employment (plan B) in the profession I had studied, and began saving like mad. About 4 years later, I had the cash to invest in the remainder of the training (well enough cash ish, Mr HSBC helped me out the last few grand

). So, hear I am, just started the IR, and have never spent so much money in such a short space of time, however, hopefully it will be worth it!

.
With respect to the Integrated and Modular courses, they differ in the respect of course structure. Now, I am not sure of the exact detail of each course (especially Integrated), but the integrated course is usually a full time course which incorporates ground school and flying spliced together and the school conducting the course must be approved by the CAA. It will last tyipcally 18 months, and you will finish with a CPL/IR with ATPL theorectical exams passed, which is termed a frozen ATPL. As I mentioned, I am not sure of the exact hour requirements, but I think you do get some relief in the hour requirement structure if you are an integrated student. Now, with the modular course, it is channelled more towards the person who wants to study in 'modules', therefore the person who has commitments, for example work, and wants to mix and match, and spread the training out over a longer period. The integrated course tends to be quite a bit more expensive than the modular, however, the pros and cons of which course you take is a whole new subject and has been discussed quite a number of times on PPRUNE, so if you are interested, utilise the search function.
Anyway, once again good luck and I hope you higher education goes well.