There is a three to six month wait to take the CPNE depending on what state you are trying to test in.  (You should check with Excelsior for specific wait times.)  The more flexible you are on your testing location, the quicker you can take the CPNE.  You can also shorten your CPNE wait time by going on a cancellation list.  After you have paid to take your CPNE and you feel thoroughly prepared to take it you can request to go on the cancellation list.  When an available date opens you have the option to take that testing slot.  Keep in mind though that your date could be short notice so you must be willing to pick up and go.