Just like you,your British pen-friend is learning school and doing to

Dear friend,

I am writing to ask you about your college enrollment process. Had you already passed all the exams? Does your college have any specific or unique requirements for new students? Also, I know you are very good at math, but you have never told in which specialization you are interested in. Did you choose finance or another field of economics? I think to choose a career is a very difficult decision, and I hope you have a well-prepared plan to follow.
For example, in my country to enroll for a university programme you have to pass school's exams which are obligatory for everyone and also write some kind of tests in university to prove your knowledge.
Anyway, I hope you are doing well.

Best regards,
Ivan