"I've never had a Coca-Cola before," Bindi admitted to ET's Lauren Zima during a phone interview from her home at the Australia Zoo on Thursday. "[My] mom always tried to limit us on soft drinks and things like that, [but] I think that now I'm allowed to have a Coca-Cola. I think?"
And the day of revelry isn't going to stop with soda. The lifelong nature conservationist has a wild night planned for the special occasion.
"I will be celebrating with my lovely little family and I'll probably play some board games, and you know, have a nice cup of tea," Bindi shared. "I might go crazy and wild and have three cups of tea that night. I'm feeling rebellious!"
For Bindi, the milestone birthday doesn't feel like much of a change, as she's always been an adult at heart. "My mom always says that I'm an 86-year-old stuck in a 17-year-old body," Bindi joked. "So I guess I'm already kind of in my adult years in that regard."
While she's excited about turning 18, Bindi admitted that her special day is a "really bittersweet time," in the absence of her late father, Steve Irwin.
"I can feel that he's not here anymore on most of the days that are really big for our family," Bindi shared. "On days like birthdays, Christmases, it's really a tough time because he's not here."
"It's sad because you want him to be right next to you and experiencing all these milestones, but I truly believe that, in some way, he is still with us," she added.
Bindi's father, the "Crocodile Hunter," was killed by a stingray in September 2006 while filming a nature documentary in Queensland, Australia. Bindi was 8 years old at the time of his death, and has spent much of her life working to preserve and honor his memory and legacy.
"He was our superhero, he was our pillar of strength, so it's hard knowing that he's not right there," she explained. "But hopefully he's looking down on us from somewhere and is really excited for these moments too."
Joining Bindi and her family for her birthday this year is her boyfriend, professional wakeboarder Chandler Powell, who she says is "actually very good" at picking out the perfect birthday present for her.
"He's coming to Australia for my birthday. As we speak he's on a plane on the way to Brisbane," Bindi said. "He was in England for a big wakeboard competition [so] he decided that he'd get me a [number] of gifts from England."
And she already knows what one of those special gifts is: authentic English tea.
"That's my favorite kind of tea, [so] he wanted to give English breakfast tea from England. I asked him if it was called English English breakfast tea, or just breakfast tea," the birthday girl adorably joked.
The two seem like a perfect match, if their adorable Instagram romance and their time together during her run on Dancing With the Stars are any indication. According to Bindi, the pair get along so well because they share a lot of interests and Chandler is willing to step outside his comfort zone.
"He understands us, he loves wildlife, loves wild places and is just ready to try," she said. "I think that that makes a big difference because there's not many people who would be willing to jump on top of a 16-foot crocodile, or wrangle snakes."
"I'm really blessed and grateful to have him in my life," she added.