17 Most Powerful Stars Under 21

Fashion icon, clothing designer, superstar singer, social media powerhouse -- Selena's entering mogul territory.

The cool best friend we all wish we had... and an awesome singer to boot!

Miley Cyrus was EVERYWHERE this past year. Everywhere. Love her or leave her, she's making powerful waves.

This young star is making a difference.

Chloe, one of Hollywood's hottest young actresses, has discussed the bullying her two gay brothers dealt with growing up.

Karlie's not just another gorgeous face. Karlie's Kookies, her cookie line, supports FEED's mission to feed the hungry.

Olympian and best selling author? Go, Gabby!

All hail Lorde, the coolest queen bee in music.

Supermodel Cara's stand-out features and fun personality make for a winning combo.

A voice like Mariah's and hit show? Ariana is definitely a powerful young star.

Everyone's favorite bombshell has graced countless covers this past year.

Ariel is one of the best parts of Modern Family, and she dealt with public family issues with grace.

This child star turned teen acting dynamo can hold her own next to Meryl Streep and Julia Roberts!

The X-Factor finalist has vocals and heart.

This Awkward star was a participant in the Live Below the Line Campaign.

Zendaya can dance (she rocked DWTS), sing, and act.

The multi-talented Good Luck Charlie beauty is making a household name for herself.