Schogini

This is a common situation when we are using ‘Marquee Tool’ in photoshop.
This is because of the ‘high value of Feather’.
It can be avoided by reducing feather to ’0 px’.

Mark the top edge of the circle shape using ‘Single row marquee tool’ and left edge using ‘Single column marquee tool’ . make sure that selection mode at the top is add. The sample image is shown below.

Now locate the intersection of two lines. Choose ‘Elliptical marquee tool’. Change selection mode at the top to selection .Click and drag at the intersection point holding shift key over the circle shape.