Welcome to this newly established forum. Thanks for your question. I'm sorry to hear of your new HIV infection -- but glad to hear you are under care and seem to have an objective perspective about your treatment.
Your doctor is correct that not all experts agree on when to start treatment is indicated in cases like yours. However, the consensus is definitely moving toward earlier treatment. Although it's a bit soon to know your viral load "set point" -- i.e. where it will settle a few months after infection -- the number so far suggest it's likely to be rather high. As you suggest, that indeed suggests a possibility of fairly rapid progression of immune deficiency. Also, the definite threshold for treatment (in industrialized countries) is a CD4 count of 500, and you'll probably go below that level in a matter of months. According to the highly respected CASCADE study from Europe, on average, CD4 declines to 500 about a year after catching HIV, and you're already getting close. See the link below.
Other factors to consider are whether you have other conditions that may affect prognosis (hepatitis B or C, substance abuse, etc) or protection of partners. People on therapy are far less likely to transmit the infection to partners than untreated patients are.
So all things considered, in my opinion you should be on treatment very soon. However, your doctor may well be equally or more expert in HIV management than I am. You don't say whether s/he is an infectious diseases specialist or otherwise highly experienced in the management of patients with HIV. If not, a second opinion would be a good idea. At a minimum, discuss my perspective with your doctor -- perhaps by printing out this thread as a framework for discussion.
I hope this has been helpful. I'll be interested to know what decision you and your doctor come to.
Best regards-- HHH, MD