He knew that she was a young girl, a student, his or anyone´s. If a 15 year old girl invites you to come home with her, would you? (no reply from shinta pls, lol)
And I agree with Ryll, burning something with oil is hard. Especially with small stuff like doughnuts. Heat the oil, check with a wooden toll if it starts blubbering when you put it in, then throw in whatever you want to fry. Watch its color. Done. If it´s chicken with bone (called "Backhendl" here in Bavaria), you turn it around as many times as needed. It swims on the surface, so one side will not be in contact with the oil.
Sure, a TOTAL beginner who cannot even name the tools and ingredients might have some trouble. But I honestly cannot imagine somebody not knowing how to fry some meat or pancakes or whatever. That´s basic survival stuff.