Her qualifying time was 4 min 36.44 sec.
The teenager finished tenth and last in the final, in a slightly slower 4.36.94, but was the fourth fastest 17-year-old.
Her next swim, in the 200m individual medley, is on Friday.
AIB Tigers’ Sarah Jane Smith swam in the ladies’ 100m breaststroke.
She finished in a time of 1 17.07 which was a personal best.
Her 50m split of 36.35 was also a PB – two PBs out of one swim is good going! Her performance, while not qualifying her for the 16/17 years final, did place her tenth in the 16-year-olds category – a good effort in her first nationals.
She says she is really looking forward to her 200m breaststroke on Saturday: ‘The 100 breast was OK, I suppose and I’m happy with the PB, but I wish I had gone faster.
I hurt my leg last week and I could really feel it in the second 50m of the race.
I have a few days off now to try and get myself fully fit and then have a really good go at the 200m.’ The championships continue until Sunday.
