Regardless of what type of license you go for, you will show good commitment by turning up early, being ready for your lesson, prepared to learn etc..
If you happen to have also passed one or more of the exams then yes I can see that this also shows commitment but I am not sure exactly how much commitment you can really show by having done all the exams in a few days! I would also surprised if a decent training organisation doesn't see something wrong with just rote learning to pass and exam a day, as you will know next to nothing at the end of it.
If you are really committed, start by getting the books, start at Air Law and read the book. Then do some groundschool (can just be sitting around with a PPL or instructor for a few hours) so you know that you have learnt and understood the book - there will be loads that you don't understand just by reading. Then, once you understand the subject do the exam.
It is a very pleasant feeling looking at the exam paper and mentally ticking off all the questions you know the correct answer to (from someone who did exams in school at 16 where I hadn't got a faintest clue what the answers were!!)
Then move on to the next one etc.. The whole aim is that each subject builds on each other, and when you have finished you have a thorough understanding of the whole subject. I am sure if you do it by this method you will more than convince any school of your commitment!