The 20-year-old next competes in the long jump on Sunday, and she is confident of picking up a medal in that event.
"I had a good start and then I'm just happy I got the final if I can find a positive. I ran better I thought," she said.
"Talking about the positive, I'm really looking forward to the long jump. That will be really good. I have a really good chance, so fingers crossed and we'll see what happens."
Breen, who is appearing in her second Paralympic Games, could also be involved in the women's 4x100m relay final on Thursday.