I don't think it's any worse that appealing to authority ("patio11 said that ....") or referencing that you were in YC. In those cases as well, quality should stand on its own. Even so, I think context helps, and it's not always the same as having lower standards.
Not commenting on whether it's good/bad, but I think it's completely different to your examples. Both of those say "here is context of my past achievements; this is an indication that what follows may be of high absolute quality"
As opposed to the "I am N years old", which is saying "here is context, which doesn't by itself indicate achievement, which may be an indication that what follows is of high relative quality"
