It just looks too big to be a plantain. Ive seen large ones, but not that large. Are there others nearby....we have similar large broadleaf plants that pop up like that here early in spring in marshy/boggy areas.
I grow plantain that gets that big and bigger. Got the seeds form @Carol S a few years ago. I feed it to all of mine all spring and summer. It goes to seed every year and new ones pop up all over the place, much to my delight.