Little Red Riding Hood? I forgot to look for her, and I doubt I would have recognized her if I did.
The secret service may be able work in several functionalities but it's primary mode is as an army surrounding the president, then as small groups surrounding relatives of the president and former presidents, and then this is the amusing it: Monitoring Counterfeit Currency.
They didn't pick this girl becuase she was Secret Service, becuase she's basically a bee without a swarm, there's more.
The worst possible story idea is that she's his wife who has been give a new face and fake memories and he knows and they're all trying to trick her into falling in love with him again.