It's never too late to go back. I am 55, have an MA in Ed, plus about 90 hours beyond that. I quit my job last year and now am back in school to get a master's in clinical mental health counseling. It's basically the degree I need to do the job I want. I was in a PhD program many years ago, but it was not for me and I am glad I went back to teaching instead.
This is the first time I've been a full time student since 1975! I love it, though I must say the program is a bit more rigorous than my first masters. If you are unsure about how you would do, you can usually take 3-6 credits as a non degree grad student while doing the admissions process. Also, I would highly recommend a prep course for the GRE. I didn't have to take it, because I already had a graduate degree, but I would have definitely needed help with the math part of the GRE.
My husband went back to finish his BS after a few years of working. He did terrible the first time around and then graduated with a 3.9 average. And he was told by an advisor that he would never make it because he had a wife, a baby, and a job, with a tough major. He's now the world wide director of over 200 engineers...