<--•----------◘---------•---------◘---------•---------◘---------•-----------◘-----------•---> 8 8.5 9 9.5 10 10.5 11 11.5 12
Jump back three dots (•) from 12 to 11 to 10 to 9. Those are your three years. Now we have to calculate the additional 1/2 year, right? Jump back one square (◘) from 9 to 8.5. That's your answer :) She was 8 1/2 years old.