Yes, the CRNA profession will be around in 15-20 years, its been around much longer than that already. As a matter fact nurses have been providing safe, effective anesthesia to patients much longer than the MD profession. Demand, yes CRNA's are currently in high demand and are projected to remain so for quite some time since the majority of the current CRNA population are of the baby boomer era and are beginning to retire.
Shadowing some CRNA's is a great idea, I did that as part of my application process and some schools require it. As far as being suited up, the extent of that is your scrubs
, scrub cap, mask and non-sterile gloves since anesthesia is generally behind the sterile field you will not have to wear the surgical gowns.
The eduation is at the Master's level currently but Doctorate level requirements are in the works, the proposed date slips my mind but I believe its around 2015 for that level to become mandatory, everyone before that will be grandfathered in naturally. The science areas you want to focus on would be organic and biochemistry in addition to the basic health sciences included in the general RN programs. Other education/professional requirements include being a licensed RN with either a BSN or other appropriate BS degree (appropriate to mean science based, like chemistery, etc), at least 1 year ICU experience and certification in CPR, ACLS and PALS, CCRN. You must also take the GRE, most schools require a minimum score of 1000.
I currently attend the CRNA program at Barry University in Miami, Florida. Here is a link for their program site which is full of information on admission req's, degree plan, course descriptions, etc. (http://www.barry.edu/anesthesiology/
) Admission to CRNA programs is very, very competitive, so if you decide this profession is for you start preparing now.
Good luck and if you have anymore questions, thow them out there.