I am in a similar situation. I am a police officer making $39K a year. I recently quit to go to CFI school and focus on it and then get a job as a CFI making around $20K. The key is becomming an independant CFI and you dont have to give part of your money to somebody. You do have to be proactive and market yourself though.

ANyway, like was said eariler. If you truly love flying then go for it. I figure if it doesnt work out then I can always go back to policing. But at least I can say I gave it a shot. If I dont at least try I wil regret it for years to come