The devoted Highlanders fan celebrated her birthday on June 5 and had been planning four days of shopping and sightseeing with her mother, Leanne, in Sydney this weekend.
However, after the Highlanders beat the Chiefs and the Brumbies beat the Stormers last weekend, setting up a Highlanders-Waratahs semifinal in Sydney, Ms Allnutt's plans changed.
The third-year primary education student at the University of Otago and her mum will now be cheering on the Highlanders on Saturday night.
''It's all just been pure luck, really,'' she said from Timaru yesterday.
''Tickets and everything were already booked ... we are looking forward to heading over in our supporters' gear and being loud and proud Highlanders fans in Aussie.''
Since moving to Dunedin in 2013, she has cheered the team on ''heaps'' from the Zoo.
Her favourite players are Aaron Smith and Malakai Fekitoa. Ms Allnutt grew up in Timaru but supports the Highlanders because her mother is from Southland.
Her brothers, Daniel and Connor, are also Highlanders fans, but father Tony backs the Crusaders.
Mother and daughter will fly out of Christchurch today and hope to return on Monday knowing the Highlanders are in the Super rugby final.
''It's going to be hard in their country, but I think we can do it.''
