Bindi Irwin, daughter of "The Crocodile Hunter" Steve Irwin, celebrated her 18th birthday Sunday with her family, closest friends and nearly 6,000 fans at the Australia Zoo.

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Bindi Irwin has celebrated many birthdays at the zoo since her father passed away in 2006. He died after being pierced in the chest by a stingray barb while filming an underwater documentary film.

The teenager posed for selfies with fans and fed crocodiles on display. Her mother, Terri Irwin, brother, Robert Irwin, and boyfriend Chandler Powell were among the attendees who celebrated.

After the festivities, Irwin took to Instagram to thank fans for their birthday wishes. Posing with a tiger cub, she promised she would "try (her) very best to make a difference in this world."

Irwin, who is also known for winning Season 21 of "Dancing with the Stars," also reflected on her life with a post that mentioned her late father:

"Our Dad, Mum's soulmate and a superhero for us all, passed away. However, since this photo was taken, 18 years ago, one life ingredient has remained, unchanged, unbreakable. That is the unconditional love that is shared between my beautiful little family and the loyalty we have to each other and everyone else who has taken this journey with us. I don't think that when this photo was taken even my beautiful parents could have known what life would evolve."