Surgery is the most favoured treatment for younger men that are eligible.
Assuming you go with this, or indeed any type of treatment, it's a question of whether you want to give yourself the best opportunity of successful eradication of the cancer and encounter the possibility of side effects of unknown severity or defer treatment (AS) until it becomes more urgent to have treatment with the risk that you then have side effects that are more severe and the longer you leave it the more chance that the cancer may have advanced further than was thought. It's a tough decision and likely to depend on your attitude towards risk. Unfortunately, at present at least, it's not possible to predict outcomes. Also, cancer does not always advance in a steady way but can take off quite sharply in some men. In this connection, try not to be over influenced by the experiences of a few men whose experience and response to treatment and side effects may be very different to yours.