My white blood cell count was 365000 when i was diagnosed with acute lymphoblastic leukemia (2012), how long would i have lived without treatment?

Can't know answer: This is difficult to say with certainty. Patients that have wbc's as high as yours are critically ill at the time of diagnosis. Factors that would influence how long someone like you would survive without therapy include how fast the WBC (and leukemia cell burden) is increasing, whether there was infection present, and whether complications of dic or tumor lysis was present. In summary, not long.

Not long: Hope you get a long-term cure, and glad it was picked up. The acute leukemias are chaotic systems and it's impossible to predict when death may come. The actual white count is immaterial, while a very low platelet count may result in a fatal hemorrhage at an unpredictable time and organ involvement unrelated to lab values can do the same.