I purchased a packet of snapdragon seeds, but I'm pretty sure the plants that grew from this seed aren't snapdragons! Can someone identify this plant so I know whether to keep it or pull it up?

There are zinnias planted around the plant in question, by the way. It's about 3 1/2 feet tall at the moment, and shows no signs of flowering. Unfortunately, the image is sideways and I can't rotate it upright! Sorry!

Thanks!