Any time.
Just make sure you use them mate.
Gain some experience with them and go back for your out of positional codes when you feel comfortable with it. Keep practicing and practicing in your spare time and at work if Possible and I see no reason why a 6G can’t be achieved in a short period of time but you need to put in the arc time.
More importantly if your not going to use them don’t do them. An expired code is as useful as no code at all.