The dandelion seeds is a good indicator: that seems to be a member of the genus Epilobium - the willow herbs.
They are ready to grow on previously bare spots and some resemble basil or mint, but without their characteristic scent and flavor.
A picture of the flower would be helpful to find the exact kind.
Obvious solution: eat one leaf. Does it taste like basil or like anything interesting at all? No? Then it's a weed.
There's the Edibility Test for doing this in the wilderness much more carefully. But in civilization worst that can happen is bad stomach. Bad come to worst visit the GP. If it's some sort of "fake basil" it's probably just grass.