Whether or not you decide to sit the exams before going, I would want to be at the stage where you can comgfortably answer all the questions in every section of the ppl confuser before you go.
That way you know you can rattle the exams off as soon as you get there and dedicate all your time to flying without worrying about swotting for exms.
If you find it difficult to get to that stage then maybe it would be better for you to get the exams out of the way before you go, and take the form with you suitably endorsed as described by Charly Zulu.
Presumably you'll be wanting a relationship with a local flying school when you come back to rent their aircraft? Why not start off with them now by doing a couple of hours to get a feel for things and make a start on the exams.