Welcome. I am one of the few on this board in active surveillance. I don't post much. I got tired of hearing that I was in denial, playing russian roulette, or afraid to face the fact that I have a PCa diagnosis. Since you've asked for feedback or insights, here goes.
A PSA test does not diagnose cancer. It's one of the strongest indicators of the possibility of cancer but only a biopsy will diagnose it. A rise in PSA shouldn't trigger treatment. It should trigger a biopsy. A PSA velocity of more than .75 ng/ml in a year is one common measure of when a biopsy should be called for. A PSA doubling time under 3 years is another common trigger for a biopsy. PSA measurements can go up or down for many reasons. Looks like yours jumped quite a bit in six months then went back down some. Only a doctor should speculate as to the reasons for that.
PSA density is another measure that is used to predict if the predicted size of your cancer favors active surveillance. The second link that Tudpock provided has a paragraph about the "Epstein Criteria" you should read. Your density comes out just over .1 by my figuring and the 3 positive cores would consitute what they refer to as an adverse finding from the needle biopsy. You didn't mention if you got a second opinion on reading the biopsy slides. Reading the slides is somewhat subjective. I believe a second opinion is worthwhile and consider it essential.
You didn't mention clinical stage, which is determined by what the doctor feels on the DRE. He may feel nothing, something on one side, or all over. A significant finding on the DRE would have tipped me away from AS.
You mentioned urination issues as a cause for concern. See your urologist. He can help ease your mind or find the cause, we can't.
Ill tell you what will trigger treatment for me. A biopsy that has a Gleason sum greater than 6. More than 2 cores containing cancer. Any single core containing cancer in 50% or more of the core. In addition, if my PSA density increases above .1, if the cancer can be felt on the DRE, or there is a significant rise in my PSA, I will get a saturation biopsy or color doppler guided biopsy. It is absolutely possible for a needle biopsy to miss the cancer or a significant portion of it. I've had PSA testing and DREs every 4 months and yearly biopsies since my diagnosis. So far, so good. Good luck to you in whatever choice you make.