You mentioned your accounting grades are mediocre. So why would you want to join a bank, where numbers and figures are not your forte? You just want to join a bank, despite having high probability of not performing well? In any case, the glamour of a banking job is like moth to fire.

Word of advice. Try going into companies for finance roles for at least 2 - 3 years experience, before applying for a job in the bank. You seemed to be confused about what you want, only knowing you want to enter the banking industry.