If my current career plan to be a biomechanical engineer is not a good fit, what area should I consider since I am interested in engineering and technology?

If you're good at math and science, generically? Then many doors are open to you. It can be very hard to decide which door is the right one for you; I was lucky enough to (from a young age) have a door in mind that I liked, and not only did it turn out to be a good fit for me, I also turned out to be pretty good at it. So I can't give very detailed advice about how to pick which door is the right one for you.

But I can say this: there are a LOT of doors here, so a good first step is to simply make a list of your options and check them out. You could be a computer programmer that specializes in writing programs that interface with physical devices (an embedded systems programmer) - the author of the software that your DVD player runs, for example. You could become a civil engineer, and learn how to build bridges and maintain dams and so on. You could go into materials science, and figure out new alloys to make stronger and lighter building materials.

A good second step is to figure out what exactly it is that you want. Me, I'm a computer programmer because I like building stuff; solving complex problems in clever ways is basically my job description, and I wouldn't have it any other way. But it's also important to me that what I'm building is something that people (customers) appreciate and need. Sounds simple, right? Well, it took me years of my career to figure out that this is what really motivated me. I just kind of floated through my first couple of jobs, and it was only after I'd had that experience that I was able to look back and see it.

So that's my advice. Spend some time looking at your options, and spend some time thinking about why you really want to design medical devices specifically. Do you want to help people? Have you got a medical device that you use, and it sucks, and you want to make it better? Do you like the challenge posed by proving that the device works (to the regulatory agencies, I mean)? Do you enjoy the idea that people to trust you enough to let their lives depend on your work? Or do you just want to be Dr. Moreau?

As an engineer you have multiple fields that you can go into if one is not the match for you. My only recommendation is to make the decision sooner rather than later or else you will be a bit behind your peers in terms study and completion. A good portion of college students change their major once they start school, so no need to worry to much over changing your mind once you get into school.

Good Luck