Those are called 'ladders' and can be common in small items. Pulling the first stitch more tightly can actually make it worse. And yes, blocking or washing it when your done will even out the sts, you can even try it with what you have now. It can help to do the first st on a needle with regular tension, then pull the yarn and do the next stitch tighter. Sometimes they can be minimized by using a set of 5 dpns instead of 4.
To knit something smaller than your circular you can try the magic loop or single loop method. ML is shown on the advanced techniques page but your circ is too short for that; a video for single loop