Rachelle Gardner posted today to let us know Two Things That Don't Help a Query.
The first is telling her what kind of socks we're wearing. I think you can tell a lot about a person by their socks, but Ms. Gardner is of the opinion you can't tell a lot about a book by the author's socks and she may well have a point there.
The second item is the one I imagine most agents are sick of people mentioning, which is how long you've been writing. Unless you've been published and/or been handed awards while writing, it doesn't make a statement about the novel, just about you. (And even then, I'm not sold that it means much about the present book.)
Since she doesn't want to see the information in our queries, she asked her readship to post in comments how long we've been spinning tales and I figured I'd repeat myself here.
The first book I remember writing was a picture book I authored somewhere around the age of eight. It was about Penny the Pineapple and her first story featured Penny traveling to Scotland, where I had just moved. So it was sort of autobiographical, except I wasn't really a pineapple. I sent the book back to the States for my grandmother, who claims she still has it somewhere. There were other Penny tales, but I don't know what happened to them.
My first novel-length book was written when I was fifteen. It was a fantasy about a girl sucked from our world into a realm of magic, only to find that's were she was from in the first place and she'd just had amnesia about her old life when she was in Florida. It was supposed to be a short story, but wasn't.
My son has a headstart on me. He dictated his first children's story to me when he was six. It was a fan-fic piece about Sonic the Hedgehog. Prior to that, he also co-authored several tales about the adventures of Llama and Spyro the Dragon. I'll let you know when he pens his first novel.