Saturday's will be her first bout since her success in Thailand where she was due to fight the same opponent twice. After winning the K1 fight, her opponent withdrew from a second bout that would have been fought under Glory Rules.
She has not fought since, wanting to focus completely on her tilt at a national title.
''I have taken what I learned from [Thailand] and just looked at what needs to be improved to make my performance better,'' she says.
Coach Brent Maharey, who is also the promoter of Saturday's event, says Emma will have learned from her Thailand experience.
''I would have thought it would have given her a bit of confidence, but she's not an egotistical person, so you wouldn't necessarily know that. But I'm sure the travelling overseas and winning a fight over there would have been a huge learning process for her and made her a lot stronger mentally as well.''
Brent wasn't with Emma in Thailand, the first time she has fought without him in her corner.
He says he wouldn't have put her forward for a national title if he didn't think she could win.
''I am quite confident, but she and I have similar personalities, and we've not cocky people, so we are certainly not underestimating her opponent.''
What he does know is that Callaghan has been beaten by a fighter Emma has defeated.
Brent says he has noticed that, as Emma gets older, she has become more focused.
''She's maturing and developing her strengths. I started training her when she was 15 and [now] she's just more focused than ever.
''In training sessions she hardly speaks and just does the work. At the end of it she has a bit of a laugh, but during training she's just really focused.
''She's always fit, always does the work, her fitness looks good and she's getting stronger physically and she has a really good attitude towards training.''
Emma says Saturday's fight will be a step up for her.
''But it's also another goal we want to achieve and that we've been planning for - afterwards will just go on to the next one.''
Last winter Emma played rugby at Te Puke High School and started this season training with Rangiuru Sports' women's team.
However, she felt unable to commit to regular trainings, and decided to focus on kick boxing.
''But it was really good training with them.''
She says the attraction of kick boxing is its variety.
''When you are competing it is never the same thing - you can always have something new whether it's personal goals or fighting goals.''
Emma is one of seven fighters from the Pāpāmoa-based Red Dragon Thai boxing gym due to fight on Saturday.
Also challenging for a New Zealand title from the gym is Yuuma Kohori who will fight Campbell Stuart from Hamilton's Tihipuke Muay Thai gym.
Brent says he is aiming for at least 12 bouts although late injuries and illness can sometimes affect the cards at kick boxing events.
Iron Shin is at The Queen Elizabeth Youth Centre in Tauranga. Doors open at 6pm with the first fight at 7pm. Tickets are $40 on the door.
