@Treue There's actually two countries between Bavaria and Hungary, and Bavaria is a very rich region, especially Munich. Obviously, you can craft your character as you like, but I think the point of the colonists being generally Eastern European was to reflect the demographics that emigrated to the new world in the 19th century - those displaced by poor economic circumstances, or trapped still in feudal systems, who looked at the US, where the sons of farmers were millionaires and had statues in their likeness, and saw opportunity. I imagine that people left Earth in Halo for the same reason, because their homes were less prosperous, hence, they tend not to be G20 countries, as Germany is.
That being said, your character having German ancestry could still be an interesting angle. They'd probably still know Hungarian though, since it's Reach's first language for everyone but the military.
(Also, apologies, I may be taking this too seriously. I just love talking about Space-Colonies, the idea of them is why I do the slug of an Aerospace Engineering degree I'm studying right now)