Preferred duration of Dick Grayson's Robin career?

[Aahz]

so which stories do make explicit mention of age in his origin?

- Secret Origins makes him 11 when he becomes Robin.
- Robin Year one has him join middle school as the new kid (so probably in grade 7 or 8).
- In his expanded Silver Age Origin Retlling he is said to be a teenager.

And there is afaik no story that shows him to be in elementary school during his time as Robin.