I had the same problem when I started taking classes.
When started classes I wanted to be a Rad tech ( I was interested in being a MRI tech )and I remember that i have even said that I never want to be a nursing student due to the thick books that I've seen students with, way too much work lol.
But as time went by realised that I could'nt just stand all day and do the same things again and again as a Rad Tech , Ill get bored too quick.
So I had to evaluate my career choice. At this time I started taking A&P and I absolutely loved the Human Body and its functions and I found myself looking at Respiratory Therapy (I even shadowed a therapist) but I realised that I would only work with the Resp System and I wanted to be able to work with entire body (if that makes any sense) lol. I then decided to talk to Pre- Nursing students about Nursing and I found myself hooked to nursing and now I am starting the program this Fall.
Im scared to death about failure, because I want to do well and now I finally know what I want , I want to be a Nurse.
Definitely do some investigating before you get into a program. I suggest you to do some research, find Rad tech forums like , call Hospitals to see if you can shadow someone. And remember it doesnt matter how hard the program is but if it's something that you really want then you'll work your way through it.
I wish you the best