Recommended MG/Children's agents to query for first-time writer?

check querytracker and agentquery.com and search for children's young adult

also what I do: every time I see an update in a thread here I check the thead and research the agency to see if it covers what I do. Then I do further research on the agents through the sites above and any link in the threads.

also i recommend going to the library/book store for books that are like yours and checking the acknowledgements because sometimes they mention their agents.

you could also google other MG/YA books and their authors in order to find out who their agents are.

Finally I'd join the Verlakay forums because it's exclusively for children's/pb/ya/mg and there's lots of talk on agents there.

also check the guide to literary agents blog by Chuck...Sambino? I can't remember.: http://www.guidetoliteraryagents.com/blog/

Hope this helps