In the past seven months, she has won eight paralympic gold medals at New Zealand championships and broken 16 national AWD records in the F46 class.
Grimaldi (17) started competing in athletics just last October after attending an AWD athletics camp in Dunedin.
''They identified me as able to run relatively quickly and jump relatively far,'' she said.
Brent Ward was an instructor at the camp and she joined his sprint and long jump training squad.
Grimaldi played netball and basketball at school but had never done any Paralympic sport before and did not have a classification.
''Mum and Dad encouraged me to attend the camp,'' she said.
''I didn't want to go because I thought they would all be too good and I hadn't done anything like that before.
''But when I got there I quickly realised there was nothing to be worried about.''
Grimaldi is quick on the uptake, and a month after the camp she was breaking New Zealand records. Within two months, she competed at the New Zealand secondary schools championships in Hamilton and won four gold medals.
It was all new to Grimaldi .
''I had to learn everything from scratch. When I compete, I feel that my disability does not matter.''
Grimaldi was born without a right arm, and it was a bit daunting when she competed at the Caledonian Ground for the first time against able-bodied athletes.
But within a few weeks she was breaking New Zealand AWD records.
''It was pretty cool,'' she said.
''It was a bit crazy. You don't think that you are going to walk in and get a New Zealand record. It made me happy.
''It was motivating to come back each week and break another record. But there was pressure because people expected me to break records every week.''
Grimaldi now holds national AWD records in her age-group in four events: 100m (13.58sec), 200m (28.39sec), 400m (66.41sec) and long jump (4.84m).
The long jump is her best event and she has extended her own record by 70cm since starting.
She had her first taste of national athletics in Hamilton in December.
The results in AWD events are determined on a percentage system and it was only after the calculations were done that she knew the result.
''It was a delayed feeling of excitement. I was named the para athlete of the meet in Hamilton and that was awesome.''
She added four more New Zealand championship gold medals at the national club championships in Wellington in March.
''It was amazing. I've had a pretty unbelievable first season.''
Grimaldi has set high targets for next season. She wants to retain her titles at the national secondary schools championships in Wanganui in December.
The highlight will be the Australian championships at Melbourne.
''I also want to qualify for the world championships in Qatar in November. If I do well there, maybe the Rio de Janeiro Paralympics. That would be fantastic.''
Her remarkable achievements in her first year of athletics have been supported by her schoolmates.
''I'm lucky to have an understanding group of friends,'' Grimaldi said.
''They are happy with how I'm going. It's really cool.''
FASTLANE
Name: Anna Grimaldi (17).
School: Bayfield High School.
Sport: Athletics, AWD, classification F 46.
Achievements
NZ records: 100m (13.58sec), 200m (28.39sec), 400m (66.41sec), long jump (4.84m).
NZ secondary school gold medals: 100m, 200m, 400m, long jump.
NZ club champion: 100m, 200m, 400m, long jump.
Queensland championships: Silver medal in long jump and fifth in the 100m.