But first, meet a Legacy High School senior who started high school with a new heart.

Now he is about to graduate happy, healthy, and grateful for his second chance.

(Cameron Durieux) I'm a proud coach, that's for sure.

He's a great guy.

-The Legacy High School Boys Head Swim Coach, Cameron Durieux, has coached a lot of athletes... [cheering] - ...but few have the heart of senior Osker Gamboa.

-Osker has such a gentle heart.

He's the guy that-- Everybody tries to strive to be like Osker, wants to be Osker's friend.

And he's the guy that everybody loves.

-Osker's mom, Kim Blas.

(Kim Blas) To see him in the pool and swimming is incredible.

-That's because after years with a bad cough and thinking he had asthma, Osker was diagnosed with a congenital heart defect.

(Osker Gamboa) What I had was called hypertrophic cardiomyopathy.

And so essentially, your muscle fibers are kinda supposed to look like this so it can pump blood throughout the body very easily.

Well, hypertrophic cardiomyopathy is, it makes those fibers all tangled up.

So essentially, it stresses the heart a lot.

-And in April of 2017, Osker got a new heart.

-I mean, the gift of life is amazing.

It truly is.

I can't be thankful enough for the donor I received the heart from.

(Christina Hernandez) When you get to see people like Osker and see what that second chance has given to him and what his family is now, his parents get to see him get his diploma on graduation.

There's so many more memories that are going to be made.

-Now, not only is Osker swimming, he was named team captain.

-I mean, when I found out I was like, I'm so proud of you!

Then I went to the closet and cried for a bit.

It was like, it's just, it's a huge thing.

-He is a leader in the pool and in life.

-He's the one that comes out and says, Hey, Coach, do you need flyers put up?

Yes, let's go get more swimmers.

Coach, do you need something for practice?

And yeah, okay, I'll need a Gatorade.

What do you got?

Whatever it is, he's always willing to help out.

-Osker is looking forward to what comes next.

-And I think at the end of the day when I walk across that stage, I'm gonna be extremely proud of myself, knowing that, you know, I did it and I'm here.

I can move on to the next chapter in my life.

-He just has such a positive outlook on life.

He knows that if you may not be able to do it today, you can do it tomorrow or maybe the next day.

He's really, he's really my hero.

-Congratulations, Osker, on all of your success.

As for what comes next, Osker wants to become a pediatric nurse so he can help kids who face similar medical challenges.

Osker, you are definitely an inspiration.

Congratulations and good luck.