I'm new at this, please help

[ChristinaMmm]

I am working on the third piece I've ever knitted and the pattern is pretty simple but for some reason mine looks nothing like the picture. This is for a simple neck warmer:

1 pair 24” size 11 needles
Using 2 strands of yarn, CO 25 stitches.
Row 1: *K1, P1, repeat from * to end.
Row 2: Knit.
Repeat rows 1 and 2 until piece measures 15”-18” (For a snug fit, stop at 15”).
BO all stitches.

I knitted about 20 rows and so far it just looks like a thick seed stich scarf on one side and knit on the WS. Attached is what it's supposed to look like:

I've never knit in the round before and I'm using the circular needles as if I'm knitting on straight needles - is that what I did wrong? Can someone please help me figure this out?