Translation of trueque

Thank you for writting back so quickly. I learned English when I was a kid, because we've always been in England during summer vacation, since my grandma used to live there when she was still alive.
Sorry that I answer so late but I was in Africa on vacation. What do you want to study in university? I think the most interesting are science studies, and it pays off, cause salaries are high.
I am glad that you accepted my offer. I would like to write letters and emails in English and if you want you can write back to me in German. I want to correct your German and so we will both get better.