Check in 24 hours before you flight and look at your boarding pass, if it doesn't say TSAPRE on it, call JB and have them troubleshoot it. You don't want to be trying to figure that out while at the airport.
It doesn't affect you, but for others that get Pre: Add the KTN to all of your frequent flyer accounts, but you will have to add it to any flights that you already have booked, adding the number to your profile won't add it to any already ticketed trips, only new trips. And if you have any business travel through Concur, whatever Concur has in your profile will overwrite what's in your FF profile. I just had this happen to me and had to readd the number for an upcoming business trip.