Your quilts are beautiful. You are doing great. As for your seam allowance problem .
When I first started sewing in 1984 I didn't have a 1/4 inch sewing foot for my machine so I improvised. I took a stack of post it notes and lined them up 1/4 inch from my needle. It was easier for me to line my fabric up with because it gave me a bigger area to see. Or you can measure out and put a piece of painters tape where you need to line up the fabric so it can help you. Just my opinion.
Quilty Hugs,
Ann W. in Indiana