911: Write With (AP) Style

Is it six-year-old girl with six spelled out, or is six in numeric form, like this: 6-year-old girl.

It's the latter. In AP Style under ages:

Always use figures.

Yes, the general number rule is spell out numbers under 10, and use numerals for 10 and over. But age is an exception. So are numbers used at the start of a sentence, which are always spelled out.

Remember these and the other exceptions we've noted through this semester.