Renee Tears had managed to beat the girl who finished ahead of her in the 5km race at the Rivercity tour event in Whanganui in November.
"I wasn't relaxed then," she said.
Coming back for the nationals, the youngster now had a better grasp of the routine of competing - mentally "getting up" for races and then cooling down afterwards, while also having had a good look at her competition the previous month.
It paid off when she couldn't believe she was ahead at the finishline from her group of nine competitors.
"I was stoked actually, my mind was racing. It didn't register."
Yesterday's indoor session began with the individual time trials, followed by the relay heats, before the first finals heading into the evening.
Begg showed she was determined to have a big afternoon, as her time in the Senior ladies 300m time trial of 30.272s was only 0.025s off her own national record, set earlier in 2015.
A few of the Whanganui regulars like Rebecca and Eden Smith chose to withdraw from indoor in order to concentrate on Sunday's marathon nationals around the Cemetery Circuit.
However, others like Tears will be hoping to do well in all three disciplines to get the overall points.
Club spokesman Ken Smith said today will be the best action with the host of finals on across the grades.
"All day the indoor programme is huge."
The big feature is the 5000m race at the end of the day.
