OK...so it sounds from your post like you've been away from nursing since 1996. If that's correct, your gut feel of "it all seems so long ago" may be correct. If you don't get this job, you might want to consider a nursing refresher course, meant for folks who have been out of the workforce for years.
That being said, if you were a good nurse some years ago, you can be a good ICU nurse right now. Has nursing really changed dramatically over the past 15 years, in terms of its purpose? I don't think so (admittedly, a statement from somebody who was active in EMS for 19 years + nursing for only 3 years). You assess your pts, decide what to do, do it, then follow up. Lather, rinse, and repeat.
If I was interviewing you, I'd have 2 main questions:
1) Why do you want to work in the (my) ICU?
2) After 16-17 years of being away from nursing, how do you plan to get back up to speed?
Please don't discount your experience in Labor & Delivery. It counts. You dealt with coworkers, pts and their families, just like you'd be doing in an ICU. Yes, there are plenty of "things" to learn in the ICU (vasoactive drips, equipment, policies/procedures), but these are minor details compared to being able to thoroughly assess your patients and, using your education/experience, ACT as needed.
You ask "What if I'm too stupid to be an ICU nurse?" ICU nurses don't walk on water. If they're lucky, they can tread water 75% of the time. They are nurses, just like you were a L&D nurse. Each specialty has their own skill sets. Accept it and move on. Entering the ICU, I'd encourage you to become OCD. Check, double-check, then re-check some more. If your pt seems to be doing just fine, then check some more. Complacency kills. Don't be afraid to be a strong advocate (AKA pushy unpleasant sort of person sometimes abbreviated SOB) for your patients.
In my ICU, one of our best nurses worked for many years in Behavioral/Psych. Others came from med/surg or ER. Some are new grads, and others have been nurses for years & years. There are many paths to the ICU.
Accept that you do not know everything. Be able to show that you know
this, yet are willing to learn & act decisively, when the situation calls for it. Accept that you will be stressed/scared as a newbie in the ICU. Trust your preceptors, ask questions, don't assume, and do your best. You will make mistakes...guaranteed! Learn from them and move on.
If you fail...so what. You at least TRIED. Yes, it will suck. Accept it, try and learn from your shortfalls, and move on.
An excellent website for ICU folks is index
. It can easily be overwhelming for non-ICU folks. Just try and pick up on major concepts.
Don't be afraid to ask to "shadow" in the ICU at which you're interviewing (preferably before your interview). This will give you a good feel for potential coworkers, patient populations, and management.