That doesn't have anything to do with the plea date. It's five years after the date the case is dismissed, and it only applies if you have a successful deferred adjudication. If so, you'd be eligible as long as you hadn't picked up any other cases during that five year period and don't have any disaualifying convictions or other deferreds (pretty much family violence, sex, or things like murder, so if you're this worried about this case, you should be fine). You're never actually "entitled" to a nondisclosure order. It's in the judge's discretion, and you can be told "no", but that's not likely if you've gotten your life together.
Ms. Foley is correct. Once you successfully complete the deferred adjudication and then 5 years passes from the date of completion you can file a motion to seal your record. There are strict rules and as noted it's not an automatic right.
Good luck, and based on the other posts in your area regarding a $20k theft, you need to focus on your defense right now rather than sealing this in the future.
Both Ms. Foley and Mr. Soechting are correct. You must successfully complete the deferred adjudication and then wait five years after the case is dismissed in order to have the record sealed. However, depending on your occupation you must also be aware that 37 different agencies even after your record is sealed. Therefore, even if you successfully completed deferred adjudication and the judge granted the non-disclosure if you work on one of those fields they would still be able to find out about the arrest. This is something you should discuss with your attorney before you make any final plea arrangements.