If you wanted to really be aggressive in preparation, you could start reading the training manuals for pilots. There will be a lot of technical words to understand, so actually getting to know the terminology and concepts around flight would be an important first step. This will also build your reading level to match what would be needed. Also, I believe there is computer software that you can get started on that simulates real flying conditions. Next, you'll need a certain amount of real flying hours before you can fly for a living, so it'd also be important to find out what's the earliest you can start earning flying hours and what programs will facilitate that. I'm in the United States, so I don't know about UK vs Germany switching, but if you have actual experience flying, I'd imagine it shouldn't be too hard to recertify in a different country if you even needed to in the first place.