Ruth Kulerman
Question: Right Time to Get an Agent?
Answer: After You are Successful.

NY Agents? Ah, LA, NY, Gilmer, Texas or Mars: I suspect agents everywhere share a common gene pool. The thinking is this: No one interests an agent quite so much as someone who doesn't need them.
I hope this doesn't end up sounding like a tirade.
Let me begin with the same sentence I will end with.

YOU do not need an agent to travel well down the road to success.

An agent guarantees nothing. You will still have to go out and get your own work until you are well known to casting offices--even with huge name agents (which as a newcomer you do NOT want).
Graduates from "name" drama colleges/universities often present a NY showcase; each student participating hopes to attract an agent. Some do. The agent interviews you. Submits you. Hopefully those submissions result in an audition. You will be competing with New York's best. And in most instances if you do not book in the first couple of auditions, you will go on the agent's back burner. This is the route of many many hopefuls, the route of many many actors.
There are ways to avoid the back burner. The obvious one is to have a huge booking percentage. But there are other ways also -- ways, that is, to be successful without an agent. No agent = no back burner.
Let me cut to the chase. An agent is not going to make your career. YOU ARE. Legit agents (film, TV, stage) mostly submit your headshot/resume to casting offices; a few agents make follow-up calls to casting offices to urge that their actor be called in for an audition. But most -- let me repeat -- MOST actors have to do their self-promotion right up until they are quite successful, right up until a producer or director calls to ask for you.
The lovely thing about courting a casting director is that the casting director can call an agent and recommend that the agent see you. The agent almost always sees someone recommended by a casting director.
Courting casting offices is a major part of learning how to self-promote. Self-promotion also includes learning how to get your own auditions. Getting your own auditions is the primary job of an actor until s/he is quite well known.
WHEN YOU ARE BEGINNING TO BE KNOWN: THAT is when you get an agent. HOW? They will seek you out.
I advise everyone not to spend a lot of time or money trying to get an agent. I advise every one to seek out CASTING DIRECTORS. Many will contact you personally. I tell all my students (even the ones with active managers or agents) to continue their own self-publicity until they are successful. And one of the most important parts of self-publicity is courting casting directors.
Create your campaign to get known by casting offices with the same kind of dedication and work that you would do if you were marketing a new product--because that is exactly what you are doing--marketing a new product: YOU. (How to self-market is a long long article itself.)
Short answer to the best time to get an agent: After you have a decent-sized resume. How to get that? The answer is another topic. But success will draw an agent to you. No, this is not a circular argument. Yes, you can get work, good work, you can get experience, good experience without an agent. Your good work and good experience will draw an agent to you.

"Court casting directors."

Note that I have repeated this several times. It is one of the most important activities of an actor. GET KNOWN BY CASTING OFFICES.

But do not try to get known until you are technically and emotionally prepared to compete. Continue training. Be prepared to act for no money until you have polished your art and inflated your ego. You will need both.
Be prepared. Seek out auditions and go to all of them. View them as performances. Of course open calls for major companies are mere formalities. But there may be someone behind the audition desk who is climbing the casting ladder and will remember you. Yes, it does happen. Book showcases, student films, short films, indy films, readings. SELF PROMOTE. Nothing attracts agents so much as an actor who shows that s/he can get work without an agent.
Make your own success. You can. I promise you. YOUR effort for yourself is more important than your effort trying to get an agent.

So I repeat my opening sentence:
"YOU do not need an agent to travel well down the road to success."
Ruth Kulerman