It's funny that you mention this, because every time I hear someone saying "don't worry about making mistakes" there's always one specific memory that comes to my mind:
as a teenager, first day in an hostel in England. Reception room full of other youngsters that of course I really want to impress with being totally cool, and so on.
I just have to ask for the bed sheets, but because of that tiny little detail...I don't.
I wanted to disappear, and felt awfully embarrassed for days.
But then I realized "After all...who cares?"