Since this is your first round (Great responses, by the way! You should be overwhelmingly encouraged.), I would wait until you get at least one response back just to see what the agent has to say. Hopefully, it will be an offer, but, if not, the agent might point out some huge hole in your manuscript that would have ruined your chances with other agents. Beyond that, I see no reason not to continue querying as long as you haven't promised an exclusive.