It's not a dumb question, but at least for myself, it is not very useful to ask that sort of thing except in the context of helping someone else. Since I've had the surgery, whatever the answer would be for my questions changes nothing. I try not to dwell on what might have been.
But, all things considered, the 2.1 to 4.6 jump in a year should be a warning. Even here we talk about the idea that one can take a little time (even months) in deciding treatment. In your case, it looks like you got the unusual case - things were progressing quickly.
Others may be able to say if there is correlation between enlarged prostate and later PCa - I didn't have any issues of that nature.
As another member here (zufus) will say, this is the Twilight Zone - there are no clear-cut answers for anyone.
I regret having to welcome you to HW. We all wish there was no reason for new members, but as long as PCa is out there, the welcome mat is out.