I applied in early in May 2015 and didn't receive a response until August. The interviewers were very kind, trying their hardest to make you feel comfortable. I had no previous engineering experience from co ops or internships, but I had a 4.0 gpa with lots of leadership experience leading my university's engineers without borders chapter. Even without experience, it was one of the easiest interviews I've had. If you want a NASA internship, focus on GPA, teamwork experience, and leadership experience