Welcome from Ontario, Canada. You have encountered a common problem of too many seams meeting. You can try swirling the seam allowances to see if that helps and you can try pressing the centre seam open to reduce the bulk. It all depends if you have a A cup, B cup or larger in the centre. I have seen lovely quilts where they take the star apart down the centre and put the halves on the edges of the quilt top rather then the centre. Good luck!