If you're interested in a career in PR, there are certain things that you need to do to prepare to get that entry-level position. I would start as soon as possible, which is college. Yes, a degree in communications and public relations is very valuable, but what's even more valuable is the experience because PR is a field about who you know. It's time to start early, building your Rolodex.
While you're in college, try to take as many public relations internships as possible. So have a job while you're in a semester at college. During that summer, take another PR job, maybe something different. Maybe you do in-house PR, out-of-house PR, brands, celebrity. Throughout those college years, intern, intern, intern, because when you graduate college and you start applying for the entry level positions, yes you're going to have a degree in communications or public relations, but what's valuable to that employer is actual work experience.
If you want to gain an entry level job out of college in the field of PR, you need to have some experience under your belt, and the only way to do it is internships. Let me tell you, all agencies need PR interns. I'm always looking for them. Spring, fall, winter, summer, my doors are open and I'm ready to take in young, college students and teach them about the field of PR.