Can't decide on what kind of job to do for internship: please help!!?

I have a Bachelors in Finance/Acctg and a Masters in Management (my bad, should have done a Masters in Finance). I don't know what kind of a job I would like to do. All I know is I like numbers, math, etc. I like desk-jobs without much interaction with people, etc. I have 0 clue of the different types of job markets, industries, etc. that exist and am not able to decide what kind of a job to look for my first INTERNSHIP?

a) Some people say I should work in an exclusively "financial" institution like a bank or something instead of working in a normal company's small "finance dept" if I like "finance" (which I'm not really sure of , either). How true is that?

b) I am even considering an internship in a CPA firm (because I have an offer) but I haven't studied Chartered Accountancy, so would this internship be feasible for my future jobs? Do CPA firms employ non-CA/CPAs easily??? Some people have discouraged me saying that I should start in a big company or bank, compared to an ordinary CPA firm or something. Is the CPA firm idea bad?

c) What are some other internship options for me?

Thanks!