Transcript for Meet the youngest athlete to ever qualify for the World Surf League Championship Tour
Reporter: It's just after dawn. And 16 year old Marx is getting in her zone. This rookie is about to compete against some of the most decorated surfers in the word. On land, she stands only 5'5". But in the water, she's a giant. She's a seasoned, crusty veteran at the age of 16. I'm exactly where I want to be, so I'm stoked. Reporter: On some levels, she's just getting started. This is her a couple years ago. These days, she drips confidence and moves with style. A ride and rise that's taken her as high as number three in the world. It definitely happened really quick. It went from zero to 100 super fast. Reporter: It's been a fruitful season, and a win at this year's super girl would be the icing on the cake. The I smell a world title on the line. Reporter: She is the youngest surfer ever to qualify for the super bowl of surfing. It's the top 17 women in the entire world. The boards that I've like won on, I'm still riding this year. Reporter: A few days before the competition, we met Caroline and her family at her home in San Clemente, California. Her parents say they saw it early. She was different. Take me back to the beginning. There were signs that she was gifted. You see her horseback riding. She was a barrel racer. She would be winning buckles and all sorts of fun stuff. Reporter: Born in Florida, she is the fourth of six children. Her brother Luke Marx is a pro surfer too. She says watching her big brother planted the seeds for surfing. I wanted to be exactly like my brothers. I looked up to them and wanted to be just like them. Every day after school I was surfing, surfing, surfing. Reporter: Still green, didn't matter. Big blast for Caroline Marx. Reporter: She developed a habit of winning. She won three out of the four divisions, which no one ever did. Then the national championship for women, the youngest girl. And it started snowballing from there. Reporter: With success came big decisions. It comes with the territory, when hobbies become business. You have to make tough decisions. Things start coming your way. We have to start taking this seriously and shielding her from the business side, keeping it fun for her. I have no wax on my board. That's all right. Reporter: They packed up the whole family from Florida and headed west, what some call the center of the surfing world. It's insane, eight of us, counting my parents, and we moved for my surfing, it's a huge sacrifice. Reporter: Caroline competes with the adults, but unlike her competitors, she's still technically in high school. You have nine books left. You have to get those done. Reporter: She's home schooled, because she's been busy with business. I live in California. Reporter: Back at the competition, the weather is a challenge. People might think the wave is a wave, but it's not. You have to become a mini weather man. You have to adjust your equipment. Reporter: She improvises. Takes what's out there. And she's on to the semi-finals. But she's not doing it alone. This is family. Always has been. It's not just the competition that gets her motivated. She's doing what she loves to do. Which is really rewarding as a parent, because you know your child is in her happy place when she's in the water. Reporter: Her parents say it's not easy trying to strike a balance between her aspirations in the water and the opportunities they create. She's very mature for her age, number one, but I still go through that when I'm with her, it's like, dad, come on, like everybody's here! I'm like, you know, could you go down over there or something? So she is very much 16 in that regard. Mom, don't bring all the kids. The it's like there are surfers everywhere. Reporter: Do you ever get concerned that on some level she's being robbed of a traditional childhood? No. I actually let them go out and go to dance at other schools and prom and homecoming and every one of them came back and said gosh, mom, it's fun, but it's not what I want to do. All I want to do is surf, and that's what's fun to me. That sounds more fun than a prom or anything like that. Yeah. I don't really feel like I'm missing out on anything. This is my room! I have trophies in here, that's about it. Reporter: Hardware of all shapes and sizes. I think the trophy's more money than the actual check I got that day. Reporter: What do you do with these checks? I cash them in. Reporter: You cash them? This is the biggest prize I've ever won. Reporter: Today I'm playing on her turf. This is a nice place to hang. I thought I'd show you guys this beach. Even the waves are small, but it's nice to hang out. A cool place to check out. Reporter: How about a surfing lesson from you? Yeah, I'd be glad to teach you to surf. It's really, really small, but it's good to try. We're at the ocean. I want to jump in anyway. Stand on your feet and get a solid base. Do not stand up straight up tall. Reporter: And I got to admit it ain't easy. At last, it's the final heat at the super girl pro surf competition. Caroline is up against three-time world champion Caris sa Moore. She's that one person I wanted to be like. Idol, but today they are strictly competitors. One of these two goddesses will walk out with a cape. Reporter: Caroline doesn't back down, but in the end, it's not her day. I got second. Yeah, we had a restart. It was a really slow heat, but it was really close. And I'm glad how I surfed this whole event, yeah. Runner-up's not too bad. Second place here today, Caroline Marx. Reporter: Wise beyond her years, she speaks like a vet and works like she's never won a thing. There's not a lot of people who say they love their job. The fact that I get paid to do what I love is pretty amaze egg, -- amazing, like a dream come true. Reporter: This is the ride of a lifetime, and things are just getting started. I'm Zachary kiesch in southern
This transcript has been automatically generated and may not be 100% accurate.