Well, I didn't pre-wash - - no problem.
I didn't use a ball point needle - - no problem.
I didn't use a walking foot - - no problem.
Conclusion?
A walking foot is a good thing - - best thing is to know which is the stretchy side and which is the stable direction - - and, keep both in the same position.
The ball point needle is a good thing for knits, especially, but if you can't afford it, just sew a bit slower.
Fleece is usually polyesther/acrylic .. <wave>