Interview tips??

I have my first interview in about 9 years coming up next Friday. I am a student and have an interview for a student nurse internship. From what I hear, competition is very stiff so I'm really needing to prepare for this interview. I have great grades but no medical experience. I have a bachelor degree in engineering and 6 years experience in that field. I have been a stay at home mom/part time student since 2002. So, I am concerned that my answers to the interview questions will be so far in the past that it will not relate. I am wondering if I should try to relate my answers to recent experiences or whatever is relevant even if it is 5+ years ago when I was working. Also, since I am not in a medical field right now I am concerned about that. I would love this job, so any tips anyone can give me would be great. Also, is a suit appropriate??? That is what we were told when I was in engineering school. A dark conservative suit.