I am a new knitter and the first project I am working on is with circular needles. The pattern calls for me to knit 12 inches and then begin my decreases. The problem is that when I started working on the 12 inches I forgot to use a marker to know where i began. Is this a problem or once I have my 12 inches I can just begin my decreases? If I can’t just begin my decreases how do I figure out where I started my rows? Thanks for the help!!!