Start by volunteering in a hospital and/or shadowing a nurse if you can for a day. You'll get a feel for the work and if you like it/enjoy it/can handle it.Lots of people think that nursing is a 'fun' job when the reality is...it's not. You're leaving a job where you have authority and responsibility to consider a job where you have responsibility but no real authority (you can't write up that same tech for smoking when you needed her, again, again, again). Consider that when you're considering nursing. Because like you, I went to school older and wiser, only to be labeled a 'troublemaker' (I am) because I won't take crap from anyone.
Hospitals these days are in a crisis mode, and if they don't see it they are fools. Health care in this country is going to face a crisis if nurses are overburdened (we are) doctors can't pay their hefty malpractice insurance
premiums and live the lifestyle they want (they can't) and we're faced with a growing population of people who do not have insurance nor the means to pay for it -- so to the ER they come. And can't be turned away. Nor should they.
Nurses get all of the work and little of the thanks. Occasionally you will have a family member tell you how grateful they are for your kindness. It helps to get thru the really bad days. Docs get all of the glory and respect, and can do no wrong (very large phallacy here).
Aside from all of that, if your science classes are over 5 years old, you'll have to retake them. If you enjoy the work, the science, the ability to work long hours with little food and no bathroom breaks, you'll be great. I would expect that you, like me, will find bedside nursing relatively unfulfulling after a short time and move out into a less 'nursey' role.
Just my 0.02.