i don't know if i should be annoyed or not

[gsh]

Work has a task that needed to be done. I wasn't assigned to do it. The person who was assigned to do it told me ealier in the week that she had gotten a data dump from a vendor, and needed to prepare a presentation to management within 24 hours, and asked me to do the task. I went to Goddard  yesterday and finished the task.

I don't know if i should be annoyed at her for not being able to do her assigned task, or glad since I now know that the task was done correctly.