Every week I read some variation of this online:
“Agents won’t even look at my work until I’ve got a few publishing credits, but publishers won’t consider me unless I have an agent. It’s impossible!”
It’s also untrue. Agents look at every piece of work that’s submitted to them. If it’s presented properly (typewritten, double-spaced etc. rather than hand-written on pink, scented paper) they’ll start to read. As soon as their interest flags, they’ll stop. If they're still interested by the time they reached the end, they’ll probably ask for more.
It doesn’t matter whether you have a whole clutch of publishing credits or none at all: if your work interests an agent or a publisher then they’ll read on, and if it doesn’t, no amount of publication history is going to change their minds.