Many Rangers have college degrees in a variety of fields. I suggest going to college and getting a degree. If you want to work in natural resources, geology, biology, ecology, wildlife management majors may be useful. For law enforcement, a criminal justice degree might help. My major was in Park Administration, which is a broad degree on park's management.
Rangers have communications, law, history, business, and types of other degrees.
If you have your heart set on becoming a Ranger, then major in something related to the field. There are a few categories as a Park Ranger in regards to length of employment and benefits. Working during the winter as a seasonal is possible too, although not as in demand. Full time employment and benefits through the government. For many seasonals, the goal is to become permanent so they can start their career.