Congratulations and Well Done!
I like the blue marking pens that wash away for marking fabric if the fabric is light enough for it to show up- just be sure to spritz with water to erase the mark before ironing, as the heat will set the marks. If you live in an area with low humidity then you can use the pens with purple disappearing ink to mark your fabric, but here in Virginia I find that they tend to disappear before I'm done quilting, do not iron over the purple marks as they will be set by the heat. You can erase them with water just like the blue ones if you don't have time to wait for them to disappear on their own. For Dark fabrics I use either a piece of soap or a wax pencil (Panda pencil is one) that leaves a whitish mark for darker fabrics or blacks. The mark does a good job of staying in place until you're done quilting and then you just iron it away.
Rob