Good idea to start with a simple pattern. Making a muslin is definitely the way to go when you are making a garment that requires extensive fitting fit to look good, but, in the case of a simple skirt like this one, I'd pick an inexpensive, fun fabric and use the following method. That way, if everything turns out OK, I'd actually get a skirt that I could wear after spending the time sewing it.
First, as mentioned above, cut for your hip size, but make your SIDE seam allowances more generous (maybe 1-1 1/2" instead of the standard 5/8"). Leave enough fabric so you can cut your waistband later.
Complete both the front piece with the pockets and the back piece with its zipper using pattern directions. Then, using longest stitch length on your machine, baste the side seams together. Try the skirt on and adjust the skirt to fit your body. Let out the side seam if the skirt feels too tight in the hip or waist (the beauty of the extra width in the side seam allowance) or use pins to take in the extra fabric if the skirt fits too loosely. Aim for a nice smooth fit in the waist and hip with no pulling or wrinkling. You can also alter the shape of the A-line if you find it flares out too much for your liking. Once the skirt fits the way you'd like, take it off and re-draw the side seam allowance to incorporate the changes you've make. Stitch the side seam and trim the side seam allowance.
Once you've adjusted the skirt to fit your hips, it's time to fit the waistband. To determine where to attach the waist band, tie a string around your waist over the skirt fabric, making it as tight or loose as you want. Adjust the skirt so it hangs evenly. Depending on your shape and the fabric, you may need to raise or lower certain areas on your waist so the skirt hangs nicely on your body. With a tailor's chalk or pencil, lightly mark where the string sits on the fabric. This is your where your waistband seam should sit. Compare this waistband measurement with the size of the waistband in your pattern; you may need to increase, or decrease, the length of the waistband pattern piece to fit your actual waist size.
Cut the waistband to fit your measurements and assemble it according to the pattern instructions. You'll probably need to re-mark the center front and side seam notches if you've added or decreased the length of the pattern waistband.
Try the skirt on, mark the hem, and finish it off. Chances are good that you'll have a perfectly fitted A-line skirt to wear this summer. And, the next time you use the pattern, you'll know what changes you need to fit your unique shape.