Do NOT let your age interfere with what you want to do!! And 40 is young! My aunt graduated nursing school at 58. My mother went for a new career and got ordained at 67. Age is going to happen to you anyway! Why not get there WITH something?!
It sounds like your scraping up money to be able to take the test so I'm assuming you cannot, at this time, afford to take a review course before taking the test again? Do you have a review book or anything you can pore over to help prepare yourself for your second attempt? You need something not only to reinforce your knowledge but also to boost your self-confidence. Maybe the school you attended has something it can offer--a tutor, a book...something.
Many hospitals are sponsoring refresher courses and other options for people who want to get into nursing. Call a nurse recruiter at a hospital in your area and ask her for the programs that may be available. These days, many individuals go to nursing school and barely pay a dime for it. Hospitals are offering scholarships
, tuition forgiveness and tuition reimbursement. Check it out.