It is a very nice, compact Aster Leena, I cannot say what species. There are quite a few of them, some going by the name of Symphyotrichum right now, and not easy to ID.
But they can be narrowed down after - flowering period, flower color, type of leaves (smooth or not), stems and so on.
What is a bit unusual about yours is the July flowering, most of them start in late July/August in Canada, but then there are many species and I don't know them all, plus even more in US.
Take notes and pictures of all the details: leaves, stems, flowers and later fruits.