Sweater beginnings

I have started the sweater. 337 stitches on the needle. The green and orange stitch markers mark off every 20 stitches. Those will come off as the ribbing starts, it starts from the bottom so the bottom ribbing will be done first. Then it gets worked up to the underarms. I will post pictures along the way. I have no idea how long this will take as this is the first sweater I've ever knit and it is the biggest project yet I have undertaken. I am nervous. Will it really fit? Will it be way to big or to tight? According to the website it is supposed to be a custom fit. We shall see. Slightly skeptical and yet hopeful. Spent a lot of money on the yarn and the pattern. The pattern itself is 9 pages long! Off I go to join in the round and start the ribbing. Wish me luck!