With the limited information you have given, the odds are it is a small garter snake. There are approx 20-30 subspecies of this snake, all with a little different markings. some are darker with rings, some have stripes that can be yellow or blue a lot of people call these reacers, but ultimately they are garter snakes. The other option could be a ring neck king snake.
One of the prior posts said it was too small to be a garter snake, but these too are born small and have to grow up