Your choice needs to be based on the expected outcomes for YOU, provided by your doctors; to that extent, it's a tough decision for you alone.
On the more general question of 'chemo now' or 'chemo later', may I commend the Rabbit Theory:
Just for a moment, think of your PCa as a family of rabbits playing in a field.
You can poison them, but for various reasons, you can only use a certain amount of poison each week.
Lay the poison now, and there's a chance you'll kill them all within a few weeks; at worst, you'll reduce them to a very small group.
Postpone the poison, what happens? You lay the poison, it kills some rabbits, but by now there are hundreds of them. you'll be laying poison for months before you get them all ... and, in fact, you may never manage it - there's so many that they're breeding faster than you can kill them.
And, yes, they will be developing an immunity, given time.
Whether you have chemo is up to you: but if you decide to have chemo, the best option is to start last week.