Help with a bootie pattern

Hi, I have a 7 month old baby with a size 4 shoe. I tried to make the following pattern using Canadiana Yarn and Size 7 needles but the booties still came out too small. Can someone help me alter this pattern to make the booties larger? I want him to be able to wear them over his socks since I dont have him wearing shoes right now. Thanks a bunch!

Booties Pattern:

Cast on 28 sts. Knit 10 rows.
Row 11: K12, K2 tog, K2 tog, K12.
Row 12: Knit across
Row 13: K11, K2 tog, K2 tog, K11.
Row 14: Knit across.
Row 15: K10, K2 tog, K2 tog, K10.
Row 16: Knit across.
You should have 22 sts.
Rib these sts for 10 rows,K1,P1 or K2,P2. Cast off in ribbing.
Fold finished bootie in half and sew the center back seam and sole closed. Trim ends.

Try using a larger needle size.

I thought about that but then the yarn will be more open and I’m trying to use these in place of shoes. I figure if I can make the pattern larger that will help.

Just figure how much more room you need, saying that the baby wears a size 4 isn’t helpful. Maybe just casting on more sts - 4 or 6 more, then decreasing until 22 sts plus the 4 or 6 more sts.

Ok thanks