I'm not trying to speak poorly of the honors program, but it definitely was not for me. I did freshman honors and stayed in up until my junior year. There is a lot of extra work to do for something that isn't even shown on your degree. The only place your honors work will show up is on your transcript and/or resume.
For example, I got my undergrad in CE and I had to lay out the coursework I was going to take to fill my honors requirements. Basically, you have to gear your studies so that you are doing "above and beyond what the standard student does.'' They wanted me to take a 500 level English course. As an engineering major, that seemed to be a complete waste of time for me. Plus, there were a lot of loops to jump through to get your honors requirements and I chose to focus on my studies/activities and view the honors program as another activity, so I dropped it.
I definitely recommend freshman honors, if you can. It's a great way to get to know a lot of people, very fast. Beyond your freshman year, I don't see much benefit.
To address the original question, I agree what someone said previously...take your time. Take some visits to ISU (and other schools, for that matter), talk to students, talk to professors, etc. Then, sit down after all that and think about what you want to do. All the while, realize that changing your major is not difficult and if you stay in a related field, should not set you back all that much. Best of luck to you!!!