Nursing is such an interesting field. If you love science, or find it fascinating to see how things work you will love it. I just graduated from a 2-year RN program so we'll see how I feel in a few years, but I don't think I will ever be bored. My first passion is Psychology, I have my BA and was headed towards my Master's when I decided that Nursing offered more diversity and job security. I too was concerned that I would go through all of the studying and jumping through hoops just to find out that I don't even like being a nurse...but people are so interesting, and it is amazing to work with patients and families. Plus, the field really IS diverse, if you tire of med-surg you can work with children, teach, be an administrator, specialize in wound care, advance to NP, work for corporations, educate on prevention, and more.
I think the trick is to know yourself and make a path that will work for you. Unlike the construction profession, you can change hospitals or career paths and it will not look bad on the resume or count against you (within reason, of course!). Something in your heart told you to take this risk, so go for it!
Edit to add: Many nurses enter the field for the pay and benefits. At the beginning of each semester the teachers have everyone in the room introduce themselves and tell why they want to be a nurse. More than half (myself included) state that the pay, benefits and job security are the main reason for entering field.