Advice on retraining to become a nurse

[har1234]

I mistakenly posted this on the Student Assistance Forum and am reposting here.

I am thinking about enrolling for a BS in nursing, with an eye to becoming a critical care nurse, or possibly a PA or NP - quite different roles I understand. I am coming at this from perhaps an unusual perspective. I have a degree in chemistry and a doctorate in biochemistry from the UK, and have been working in academic publishing for 19 years since that point - I am 46 years old and a US citizen, based in MA. I am one of that 10% - a corporate layoff. I have decided that I want to retrain and apply my aptitudes and skills in a way that really matters. I am interested in whether any one has experience like mine and how you found becoming a nurse? Perhaps someone could give me advice on paths to follow, and perhaps comment on the goals I have set for being a critical care nurse, PA or NP?