This is a variation on the standard question of goal-setting but with an accounting focus. They want to see that you can overcome obstacles and set your goals high. If you think that you haven't set or achieved goals in this area, then look to your education. You set the goal to become educated and take on this career, so you achieved whatever level of education you have.
If you're self-taught, that's also a goal. Discuss a project you took on or how you became interested in the field.
"When I was in college, I worked as a receptionist at a dental clinic four days a week. Their accounting clerk walked out on them in the middle of month end. They asked for help because at the time, I was an economics major and somehow they thought that tied together. I dug in and learned a lot about accounting on the internet. When I got stuck, I went to YouTube and found these walk-through videos that taught me so much. Shortly afterward, I changed my major to accounting because I fell in love with the process."
"The biggest accounting goal I set for myself was obtaining my Bachelor's degree in Accounting. I started school with no idea what I wanted to do, but after a lot of research and development, I was able to narrow the field to accounting. I set the goal of achieving my Bachelor's degree early to start my career. I was able to double my class load a couple semesters in a row and graduate a year early."
"When I started working for a company that was newly public, they had no structure for a lot of their departments. I was tasked with finding a way to help structure the accounting department. I was a business analyst so I did the majority of the grunt work of compiling who did what and documenting everything. My goal was to document in such a way that everyone could understand the details of their job functions through the documentation with no surprises. From my understanding, the company took my documentation and use it as job descriptions when they post for open positions."