I think you have common groundsel, Senecio vulgaris:
https://www.thetortoisetable.org.uk/comm ... -05-21.jpg
it's a weed, but I think a kind of pretty one. If I am right, those buds will open up into bright yellow flowers:
https://whitman.wsu.edu/wp-content/uploa ... e_0025.png
but watch out, because the flowers then turn in to dandelion like fluff and spread themselves all over the county. Also the plant is poisonous to cattle and horses that eat it and toxic to humans (IF they eat it).
So what is a weed is always open to definition, but I think most people would say yes, this one is a weed.