I always knew, when I was growing up, that I wanted to work with animals and the environment. The first bit of advice that I would give is that it is not important to know exactly what you want to do at your age. Throughout high school they always put so much pressure on students to know what they want to do for the rest of their lives. This is crazy! You don't have to know exactly what you want to do because you haven't experienced any specific classes about particular fields. If you want to work with animals or the environment I would suggest looking into zoology, biology, environmental sciences or animal biology. You can work towards any science bachelor's degree and obtain a job that deals with animals or the environment. In college, I would recommend looking into internship programs and volunteer programs that specialize in what you think you want a job in. Internships will let you know if this is what you really aspire to go into or if you should potentially look into different types of animals or different types of environmental based jobs.