Using pretty as the nr. 1 correct translation before teaching the actual word for pretty/beautiful is hazardous. When translating melko in my head pretty didn't even come to my mind, quite and rather did. Please let's use a more specific word for lessons if one exist and skip those that can also mean something very different. Quite should not only be accepted but preferred for this and should definitely be added to the hints before pretty to avoid confusion.
Except British English and American English use "quite" in nearly opposite ways. "Quite small" in British English would equate to "kind of small" in American usage, and "quite small" in American English would translate to "very small" in British usage.
I am American. I learned this somewhere on the internet.