A year's income in reserve is a good rule:
Trying to learn a new profession isn't enhanced by stress about making next month's bills. Unless your current sphere of influence is made up mostly of business people, it's likely that your start in commercial real estate will be a gradual one. Be prepared.
If you do have enough in reserve, you should start in Commercial:
With enough in reserve, the faster you get your feet wet in commercial the better. If your goal is to be a commercial real estate agent or broker, the experience will be gained much faster in a full-time position in a commercial brokerage.
Do you have the confidence to work with the commercial client:
Prospect-to-closing is usually a much longer process in commercial real estate:
Be sure that you'll be able to work with a client for months, with a great deal of research and property analysis before an offer is even considered. Then, after the offer, the process of due diligence is much more involved in commercial property transfers.
Commercial real estate can be quite lucrative if it's your cup of tea:
There are few professions that are as financially rewarding, but one must be prepared for the delay until the first commission and the time between deals.
Many would tell you that this is a much more difficult niche than residential real estate. You cannot rely nearly as much on the property selling itself by hitting an emotional chord with the prospect. You'll be called upon to participate in a great deal of analysis of data and financial information. Your clients will be more into the negotiation process and require more of you in the skills that will get them the best deal.
It's different, but if commercial real estate is for you, the rewards can be great.