I took an approach probably more like you did when you were sewing clothes for your daughter. When I first started sewing clothes I chose simple patterns that I knew were within my skill set. As my sewing skills improved I chose patterns that were progressively more difficult. One part of the pattern might be a challenge but the rest I knew I could do. When I started quilting I did the same thing, my first few quilts were pieced from rectangles and squares. I chose patterns where you didn't have to worry about matching seams from one block to the next, ex. rail fence, crayon box from Bonnie Hunters site. Then I chose a pattern with a few half square triangles and a few seams to match from one block to the next. As my piecing skills progressed I would choose patterns that were a little more difficult and and I also increased the size of my quilting projects. For me it was important to pick something I could complete in two to three months and that were challenging me to increase my skills without being too frustrating.
As far as to when you feel confident in your abilities, in my opinion that is kinda determined by your personality. There are quilters who create quilts that could win awards, but never enter or show them because they don't feel their work is that good and there are beginners that are very confident from their first project on. But perfection, is something that I don't feel is achievable in quilting, there will always be something you'll wish you did differently.