Welcome!
I found the rotary cutter challenging when I started as well. Check out the cutting mat you are using. Some of them are more like hard plastic and some are the softer self healing mats. I started on a hard plastic one and I found it felt like the cutter would sometimes almost slide out from under my hand when I used it. I like the softer ones much better, like the Olfa mat one of the ladies suggested.
Not sure where you live, but there is a great store called Marshall's Dry Goods in Batesville, AR that has Great prices on fabric. Mostly, just enjoy the journey. A quilt out of the heavy fabric might be the perfect thing for trips to the park. Or, how about a quilted dog bed? I made one with the fabric from an ugly fabric exchange--it turned out really cool! But, some of the fabrics didn't hold up so good.
Good luck!
Good luck!