Hi, wanted to over-seed before the winter (Boston, Ma). I pulled up most of the easily identified weeds, but have no idea what type of grass this is and if it needs to go. Any help would be great.

If it is indeed a weed and since it is spread throughout my lawn, can I use Round Up to in those areas and if I do will it allow me time to still over-seed before the winter? And help would be appreciated. Thanks.