We have them wild as well, but I've had Sora since she was about 4-5inches. About 3 years now...
But they're over running the Native DiamondBack Terrapins, so now we've got a conservation act going for them.
Usually Females get to be about 12inches averagely, but have been known to excede a ruler from time to time. Males, not so much... You probably got a female.
They are opportunistic, and also learn that they can be fed by humans, so I'm not surprised you caught one on a line lol. Sora used to be handfed, until someone told me it's not good to handfeed, cause then they won't eat otherwise. Now I alternate.