Easy Baby Pretty Poncho--How to make it larger?

I keep searching for a poncho pattern done on circular needles and I keep ending up back at this poncho http://home.howstuffworks.com/easy-baby-knitting-patterns6.htm. The problem is that it is sized for 18-24 months and I need it for a 6 y.o. I’ve never done circular knitting or altered a pattern–it’s been scarves, blankets, dish clothes, and wraps, so far, but I’m looking to expand my knitting.

So, can I do this? And how? Or should I go with something similar, but I don’t like as well (“Knitting Pure and Simple” Poncho #243) that comes with size adjustments?

Thanks in advance for any advice!

It may be easier to do a top down one using a raglan sweater pattern generator. Instead of separating the sleeves and the body, keep increasing on every 4th row. I find it amazing they use that many stitches in a bulky yarn for a toddler pattern. You might try it and see if it comes close to fitting your daughter.

You could always take that pattern, double-strand the yarn and go up several needle sizes.

Something to consider is starting with a provisional cast-on, so that as the child grows, you can lengthen it (buy extra yarn). It’s not nearly as difficult to unpick a BO as it is a CO edge.

But looking at that pattern, the circumference of the bottom edge is 51 inches… that would almost fit me.

What I would probably do with that is go up a needle size (or two), use a provisional CO, and start with round 4. Once you have the decreases, shoulder and neck done, and you know that that portion fits your LO, go back to the CO edge and work the length you need, then add rounds 3, 2, 1 and BO.