Doing it wrong

I went here on Sunday morning to enjoy some cat and kid free knitting time with a cup of tea and an orange and currant scone and one of the other me-timers comes up to me and told me that she has made that exact jumper twice! And I'm pretty much doing it all wrong. She was really lovely about it and it was hard to be cross but I'm apparently using the wrong kind of wool (there are different kinds of wool?) and it's going to be pretty baggy on my already pretty gigantic child. I'm determined to finish, at least I'll have learned some new stiches, right? Jesus, how zen of me.