Well, the good news is that it is not mugwort.

This time of year there are three plants that look quite a bit alike which include various Solidago varieties, fall Aster varieties, and the weed called Marestail/horseweed (Conyza canadensis), which looks like this:

https://extension.umd.edu/resource/horseweed

We often wait later or for flowers to know for certain. The fact that they are growing in a line like that somewhat suggests Solidago. They have thick white underground runners between plants. You could gently dig/pull one up and see if they are connected (though they wouldn't necessarily have to be if they are new).

Both asters and goldenrod would be pluses. Horseweed gets small flowers in a plume sometime July or after, with asters and solidago later in the year.

Christine