Red eared slider turtle

Okay so I found a turtle in oklahoma a few months ago...and I brought him home to colorado. He lived and I found out that he is a red eared slider turtle. But hes no bigger than 2 inches...is he supposed to get any biggger?

your turtle could get to be as big as 12 inches long lengthwise, it could live 5+ years, red-eared sliders are the typical "pet shop" turtle.
my parents had a couple of these turtles and they were quite content, until they got larger and my parents returned them to the wild.

good luck with your turtle.