S’mae Tatjanaprelogknightg?
You can of course use whichever you feel most comfortable with, but you will hear the short forms, so it is at least good to be able to recognise and understand them. The more you do this however, the easier they will get, and soon you will be using the short forms just as comfortably as the long forms, just let it happen naturally by working through the challenges.
Hwyl,
Stu