Back in the official ABC podcast for episode 2×22, Eddy and Adam confirmed that Emma is a reluctant hero who gets freaked out a bit by her own magical ability. Also, when she combined her magic with Regina, she was able to save the entire town from the fail-safe. E &A have strongly hinted that we’ll be seeing a lot more of Emma’s magical ability in S3. There was also a spoiler that Regina might train Emma to use magic. Both Rumple and Regina have been repeatedly amazed by Emma. She is destined for greatness. So, I think there are plenty of reasons to believe that not only was Emma destined to break the curse, but she is also meant to save everyone repeatedly, as she did in the end of S2.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy