Finishing the Unfinishable Project 2--Myrtle the Turtle Baby Bib

This bib gets the name "Myrtle the Turtle" from my mom's childhood pet turtle of the same name. Myrtle met her(?) unfortunate demise when my grandmother accidentally slammed their enormous front door and squashed the turtle. Terribly sad. I think the next turtle was named Lyrtle. I like the idea of upcycling--using something older to make something novel. So when I saw the idea to make bibs out of old t-shirts, I loved it.

Old t-shirts. Something we have legion of at our house. My husband loves free t-shirts. He probably has four dozen. So I decided to try making a baby bib from one of his shirts. The first one was a giant FAIL. I did not put any interfacing in it and it stretched like crazy. The sides were terribly puckered. I actually threw it away. Even after I monogrammed my son's first inital onto it. It was that bad.
I had cut two t-shirts up for this project, however, and one of them still lay pinned in my sewing box. I decided to finish it. But this time, I added some fusible interfacing. I ironed the interfacing to one side, sewed through all three layers (leaving a gap to turn the bib):

then peeled off the paper to reveal the other side of the fusible interfacing.
I then turned the bib, ironed it again (to fuse the interfacing to both sides) and topstitched around the edges:Then, I added some velcro:

Myrtle was already cut from felt. I'd even cut her a piece of fusible interfacing. After fusing it to her, peeling off the back paper, and then fusing her to the bib, she looked like this:

She was crying out for some topstitching. I used orange thread!

Done.

Lots more bib ideas!
Little Birdie Secrets
Make it and Love it
using scraps

The only problem I am still having involves the fact that it is still puckering at the edges. Is it just because I used knit fabric? Or am I doing something incorrectly? I did iron it. It still puckers. Here is a picture so you can see what I mean...