I am pretty much in the same boat as you but you have to look at the programs your interested in first and then determine your path. I would first suggest looking at the CA board of nursing website and see which schools catch your eye whether it's a bsn, absn, adn, msn or other nursing programs. I know that your 3 sciences have recency but that's not always the case. For instance, LA Community Colleges take only 1 repeat no matter how old the courses are from when you first took them. Other schools are 5 or 7 years and combine English and another course into their prerequisite gpa requirement. You should have most of your prereqs covered since you already have a BS so it shouldn't take too long to finish the rest of your requirements unless there are other factors (competitive courses, priority registration at the cc, etc.). I don't think you should worry about age, as long as it's the path you want to take then why not.
I hope this helps you a bit and I do agree that you should find volunteering right away if you don't have any type of experience they are looking for in their admission requirements. Btw, if you are in the la area then look up trifecta at ELAC and you can get it done in one semester but there is dedication and time involved as it is 3 hard sciences in 1 semester, 5 weeks each.
Good luck with everything.