I'm 64, PSA 4.9 prompted an MRI which also showed Pirads 4 and 'changes' to my prostate but these were contained. That prompted a biopsy which confirmed cancer with a max 4mm lesion. That prompted a recommendation of AS. All of this on the NHS. Following that I saw both an Oncology & robotic surgeon who confirmed that AS should be fine but that given my diagnosis both offered 'cure' if I proceeded. After much deliberation I'm having RARP on 8/04.
It appears that one's age and therefore one's life expectancy plays a huge part in the NHS recommendation process. Given what I know now I'd suggest you ask for a biopsy and get a full diagnosis and then you'll be in a position to make an informed decision as to your next move.
Best of luck