I am assuming your post suggests you are uncertain about a decision you are about to make.
Is there family history to consider.
Are you concerned about the side effects of treatment as when you read through previous posts it's a matter of personal choice and some get through treatment with minimal side effects and others cop quite a few!
Currently as I comment here there's an article on TV abt exercise, mental health and chemo et cetera 45mins, 3 times/week some sort of exercise
Some on here talk about the importance of going for a walk
https://www.bcna.org.au/health-wellbeing/physical-wellbeing/exercise-and-staying-fit/#:~:text=Getting%20regular%20exercise%20during%20and,lymphoedema%20and%20lowered%20bone%20density.
As @Cath62 mentioned above reasons are personal and varied.
Treatment offered by the medical team is tailored to your situation
Please be comfortable with your decision
Take care