I don't get tired of it because I don't always offer the information up unless I think the person is truly interested. I think to the lady's comment of:
Her: "Wow. You waited a long time to go to school. What, were you in the military or something?"
A simple response of, "I'm a bit of a late bloomer and just started college later than most people." If they want to know the why behind that, I usually say, "I just decided to join the workforce right after high school. It took me a few years to arrange college into my life, but it's worked out for the best."
Although I understand people wanting to get involved in a conversation, sometimes the questions they ask are all to nosy and personal.