There's been a lot of confusion about the Secure Flight Initiative on all levels. The bottom line for the OP is that if you purchased your ticket before compliance became mandatory that it doesn't matter.

Nor does it technically still with the name on the reservation/boarding pass. You need first/last names to match the I.D. presented but only in a secondary internal name field that is transmitted to the TSA (Homeland Security) along with your date of birth and gender does the full name have to match exactly. That is not justified (at this point) with the primary name field that is picked up for boarding pass issuance.

Of course it's going to be up to whomever you run into at security to interpret the confusing mish-mash of information that's been put out there. I've been told by my road warriors that the worst they've encountered to date is being pulled aside at the security check point and having a name discrepancy logged by the agent.

We're just urging frequent travelers to begin the process of getting their full legal name in place on reservation profiles and modifying any mileage/loyalty program profiles to match. Easier now than later when (if?) it becomes mandatory. My opinion is that the fewer excuses one gives security and the TSA to take notice of you, the better.