Me.
Planning is good -wish I had! I got fed up working for MIME's (minor intellect, major ego), found wearing a suit too restrictive, chucked-in the towel, moved 250 miles and started again doing something I enjoy!
To start planning a career you should decide what you're interested in and what you're good at then decide whether there's a market for that and whether you want the 'freedom' of working for yourself or the 'stability' of a regular wage.
Photography covers such a wide range; Portrait/Wedding-Social documentary-Fine Art-Landscapes-Forensics-Advertising-Magazines(themselves covering every subject under the sun!)-Glamour-Lifestyle, etc, etc...
Decide where your interests lie - perhaps start with what magazines do you regularly read and narrow it down from there (do you want to do forensics or shoot for Vogue or Canal Boat Monthly?)
Then decide how you want to get there - do you need any specific qualifications?
Whatever you decide it will be hard work but may just possibly be worth it. Good luck!