Hi djla,
You do not need to pass any test before approaching a flight school.
In fact, as you say you are completely new to aviation, I would recommend you to visit a flying club or a school quite early in the process, book a trial lesson and actually see and feel if this is what want! A trial lesson can be credited towards your training hours if you get the paperwork right - so it's not a waste of money!
At this point, I think I'd ask myself some general questions which should more or less dictate the course of action afterwards. What are you looking for in flying, where is it going to take you? Do you want to fly for a living or as a hobby? Do you want the license quickly, or would you enjoy the training so much that it can take 1 or 2 years to complete? Are you on a budget or do you have money to spend?
Then start making decisions: What kind of license you need (EASA PPL is a good starting point for private flying...), where you want to do the training (clubs or schools in UK, intensive course in the US, ...) etc. You will probably have more detailed questions in the process of making those decisions. Come back here with those questions. ;-)