Well, i'm not so sure as my other turtle who is about 3.34 inches has a tail thats much smaller, and its claws are also not as long.
One additional info is that my turtle is only less than a year old but is already 3.5inch, when i got him he was 2 inches and had a little shell curling. It was only later on that i found out his previous owner ( my friend who did not want it anymore) had been feeding it random amounts of food anytime he walks by the tank

he tells me that usually my turtle would be fed 3-6 times under his care. I only had him for about 4 months, his previous owner had him for about 6 months i think. And so I think that is why his growth rate is so high. Anyway the obvious sign to tell if its male or female would only appear when he's about 4 inches right?
Really hoping his a male, not sure if i would be able to house two adult females