I just ordered my first FG bike. I ride a lot, but a normal road bike...gears..brakes...etc.

The bike I ordered has a Front Brake but no rear, I am about to order a rear brake but thought I'd ask if it is worth bothering. I'm new to fixed gear, as in New...Should I order a rear brake or just go with a front only?

For reference, my new bike starts with a K and ends with pro....but that is not the point of this thread.