Hi there and welcome!
Start where you like! If you have sewed before, ie clothing I believe quilting will be a snap, changing from 5/8" seam alllowance to 1/4" is hard to accept but that's the way its done.....I admire you for not being afraid to try SNW....but I think you need to start with say a trip around the world baby quilt, just to work out the bugs of the machine, how to use the cutter safely and accurately, find your 1/4" seam allowance(the most critical thing in piecing other than acurate cutting)....these will insure your SNW project will go much smoother. My beginning quilting class starts with a simple nine patch called shoo fly, which is made into a mini quilt and then transformed into a pilllow by some or more blocks are made that become a table runner, or sofa quilt....I think you need the practice especially if you have not used your machine a lot and need to learn how to use the rotary cutter both as important as any aspect of quilting. The biggest obstacles in beginning quilting classes are: operating the machine, the rotary cutter, the cutting board(almost everyone starts too small, buy minimum of 17x 24, full width of fabric will fit folded IMPORTANT! and a 6 x 24 ruler preferably Omnigrid all others can be difficult to see on certain fabrics) , and marking a good 1/4" mark on your machine so that you have a consistent 1/4" seam allowance. Otherwise jump in anywhere, put perfection aside for first couple of blocks and just have fun with the fabric and the whole quilty idea. You will find your own level of perfection/comfort. By the way, my first quilt was a queen sized Trip Aound the World cut with scissors! DON'T use a scissors, Yikes! it was way harder than it needed to be. Great first books are any of the Quilt in a Day by Eleanor Burns, Quilts for people who don't have time to quilt by Marti Mitchell, and Porter and Fons Complete book of quilting(really probably would not need to buy another book ever) .....all are clear concise, with good illustrations. Again, Welcome and ask any thing you want even if you think you will sound stupid we have all been there!
-- Mauvice in Central WI USA