Welcome to Trulia.
Are you going to start part time or full time?
If part time and your other job/career is providing the income you need to make a living then yes it may be good thinking on your part (depending on many other parameters...).
If you want to start full time I would suggest having at least 1 year worth of saving as you may not be able to generate a decent and consistent income before a year or more...
Also as most agents are individual contractors you may think of it as running your own business with having to pay for every cost involved and more from your own pocket. What does it mean in term of monthly cost? -different agent- different monthly cost ranging from a few hundred dollars a month to XXX thousand dollars a month...
I hope it helps,