There’s been speculation that this character could be Barry’s future daughter, who would have traveled back in time considering Iris isn’t even pregnant yet.
That sounds like an astronomical stretch without explanation, but there’s definitely something screwy happening in The Flash.
While that hasn’t been revealed, Barry did make a reference to needing more diapers in his post-Speed Force delirium, which led many to speculate that he and Iris could be expected one or more children soon.
Beyond the fact that Barry seemingly predicted his arrest for the murder of Clifford DeVoe in the premiere, there’s also that mysterious caterer from the crossover that seemed to know Barry a little too well.