True.. If you already have a Diploma and wants to further in a university it takes 2yrs instead of 4yrs but it would be very convenient to do in your place of acquiring the Diploma but not sure of its effect or acceptance in another country which the Diploma wasn't attained.
That's why I said 4yrs. You can apply for the 4yrs Bachelor program of your choice, then after getting there you can explain things out to the school's International office or a potential school advisor for profound info