A stunning emergence onto the international scene saw her earn a late call-up to be a part of the biggest event in the sporting calendar.
She did not disappoint.
A bronze medal in the T35-38 women’s 4x100m relay team was complemented by a fifth-placed finish in the T38 100m and eighth spot in the 200m final.
Fast forward four years and Breen is again fighting for glory on three fronts.
This time, though, she has added a field event to her track repertoire, with the long jump taking the place of the 200m, which is not offered in Rio.
And it is a challenge The News 2013 sportswoman of the year is relishing, having grown in both size and stature since London 2012.
Breen said: ‘Last time in London 2012 I was only young and I wasn’t very strong, I was very weak at the time!
‘I was lifting 1k dumbbells and now I am lifting 10k dumbbells – you can see the improvement and how strong I have got in the last four years, through hard work.
‘Last week I got a personal best (PB) in the 100m at the Loughborough International, which was really exciting.
‘I knew I was in a good shape – it was the best shape I had ever been in going into a race.
‘But I was quite annoyed that I didn’t get a good start – I didn’t hear the starter because I am deaf, so it is harder for me!
‘It just shows I can run even faster.
‘But it was really exciting to get the 2016 season off to a good start with a PB.
‘Yesterday marked 100 days until the Paralympic Games and it is a very exciting time for me.