I think the person in the thread who said take your time was dead on.. What is it YOU like? For all the potential fields you mentioned, you will need a basic background, at least, of science, math, english/communications. If you keep an open mind, you can learn a lot once you get here. Most if not all high school folks like you really dont know or really have a need to know the specifics of some of the disciplines. Ag genetics is cool but damned narrow. Know that with most any biological field, you will need to apply genetics, so dont limit yourself. As for the engineering fields, they are important, but many learn that they arent exactly their cup of tea for a variety of reasons. Actually, that goes for any prospective major. But.. the key is, get a good base in preparations, and you will have the ability to tailor your education as needed as you go, hopefully in the first couple of years.
Thanks..