I'll be the buzzkill for the group.
Is she taking any information from you for tax purposes? If not, I'd caution you about posting any of the shop's info online--because that means that she's not paying taxes on any of your labor. (You're also not paying any federal or state taxes on what you're getting in exchange for your services either.) Additionally, I'd wonder about her wholesale vs. retail costs of the fabric, and wonder how far below minimum wage I was actually being paid.
This also leads into workers compensation insurance questions. If you're not truly on payroll, it would be an interesting situation if your rotary cutter slipped while you were working and required stitches. What if you slipped and fell in the stockroom?
Would I do it? In a heartbeat.