I think it's great you did this and she's willing to pay a nominal fee. It's great experience for you. BUT!! Unless you want all other members of her guild or her friends coming to you to quilt their tops inexpensively, you have to make it clear that this was a one-time thing. Others will expect the same pricing even as you get better at the quilting. Decide if you want to quilt for others in the future and determine your pricing ahead of time.