If you already have a bachelor's degree and the pre-requisites, and you happen to live or want to live in one of the 18 states that currently licenses them*, why not consider becoming an Anesthesiologist Assistants instead. It's basically the a specialized type of PA involved in, you guessed it, providing anasthesia under the direction of an Anesthesiologist.
I make the suggestion because in order to become a CRNA, you're looking at 18 months or so to BSN/RN if you take an accellerated program, then you usually need a year of critical care nursing experience to even be considered for a CRNA program, then the program itself, another two years. By the time you get to that point, the DNP might be required, meaning it's even longer, and part time makes it longer still. At that point, you might as well go to medical school. If you're really sure this is what you want to do, just cut to the chase, get the master's degree now, and skip the interceding parts.
Just something I thought I'd throw out there for you.
* - As far as I can find out, those states are: Florida, Georgia, Colorado, South Carolina, North Carolina, Alabama, Kentucky, Missouri, New Mexico, Ohio, Oklahoma, Vermont, District of Columbia, Michigan, New Hampshire, Texas, West Virginia and Wisconsin