What interested me in the field? I can echo some of the comments already made, and add some. My strengths in High School were Math and Science. I have a curious need to understand WHY things are the way they are. I like to fix things. I like to work with my hands. I like computers as a tool. I like almost anything technical. I dislike open-ended questions. I dislike essay questions. I think these traits are pretty common among engineers. We are sort of between a Journeyman Machine Builder and a Professor.
How can you find our more? Your college Career office likely has many vehicles (interviews with working Engineers, personality and skills assessment tests, etc.). Internet information. ASME. Talk to your ME Professors and ask them their experiences! Talk to your peers who have completed some ME internships in industry. What did they like and dislike about their experience?
The ME degree will definitely pay for itself monetarily, buy you are not likely to get rich. It will afford you a nice middle or upper middle class lifestyle. If you want to get rich, ME is merely a stepping stone.
Will you be happy doing it 40-50 hours per week? If you do choose the ME degree, what type of ME work interests you? ME is a BROAD FIELD! ME's can do software, sewer systems, building structures, automobiles, space vehicles, nanotechnology, bioengineering, heavy industry, administrative desk jobs, thermal simulation, HVAC, refrigeration, etc. Heck, I know a successful home builder who graduated as a Chemical Engineer!
Finding something you want to work on that lights your fire is more important than which degree you have. The degree will only get your foot in the door. Spend time looking in the mirror to find out what motivates you.