Amelia's 43.61 secsonds effort in the 50m breaststroke beat her previous time by 1.7s before she took three seconds off her best 100m time in 1:38.05.
And the 10-year-old said she was only worried about beating herself.
"My main goal was to have fun," Amelia said.
"Being able to do well made me really happy because there was lots of great swimmers. Racing against them only helped me to get better."
Amelia also impressed on the team front after competing in the 4x50m medley relay and 4x50m freestyle relay, which resulted in fourth and sixth place finishes respectively.
And she learnt an important lesson from swimming with others.
"I used to think swimming was all about the individual," Amelia said.
"But you need a lot of support from people if you want to do well. And that doesn't just mean your family, but other competitors and coaches as well."
Away from the pool, the 208 Primary School student enjoyed the social aspect - most notably at the end of competition when participants swapped their state's respective pins with one another.
"The pin gave me something to remember the competition," she said.
"Being able to swim was great but sharing the experience with other swimmers put a smile on my face."
Amelia will now turn her attention to the Victorian Country Short-course Championships in Ballarat this weekend.
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