Never ever turn down command.
Do so and you may wait 20 years or more for the opportunity to come around again.
Nothing wrong with turboprops either. I spent two years driving one round the UK and near Europe and that is where I really learned to fly. The fact that 12 year olds can buy their way into the RHS of an Airbus has got to tell you something about the magnitude of the challenge there.
And before everyone starts, I have indeed flown the Airbus and currently reside in a 747-8. So TP's never did me any harm. Quite the opposite in fact.