While his eventual sentence was short enough to allow an application for home detention, Tait, through counsel Vicky Thorpe, declined, saying he would find it difficult to comply. Judge Jonathan Down commended him for his insight.
Ms Thorpe said Tait had recently shown more insight into his offending and regretted previous remarks he made to a report writer.
The court heard Tait loitered about the Grant Brothers store before attempting to rob the shop assistant. At one point he tried to access a cabinet displaying knives. When she approached to offer help, he refused and briefly left the premises.
When he returned brandishing a ballpoint at her and demanding the contents of the till, the assistant initially thought he was joking.
After a second demand she still refused to act and Tait left the store empty-handed.
Judge Down said although the attendant would not have anticipated injury (given the nature of the weapon), the experience had shaken her.
In a Victim Impact Statement she said she now felt extremely uncomfortable whenever she saw large groups of male teenagers. She worried something similar might happen and had to have someone with her when she was in the shop.
Tait had relevant previous convictions in 2011 for common assault and disorderly behaviour. In the Youth Court jurisdiction up to 2010, he had a number of findings against him in relation to violent offending. None of these were particularly serious.
A pre-sentence report said Tait posed a high risk of reoffending unless he dealt with his harmful pattern of alcohol and drug abuse. A psychiatric report showed he was not mentally disordered.
Judge Down told Tait if completed, robberies of the type he had attempted - involving small shops and vulnerable shopkeepers - drew sentence starting points of four years imprisonment.