Fortunately,difficult child knows all the steps, it's just his initiation to the next step. One of my infamous lines is "stop stopping". The planning to automatically go to the next step is natural to us but my difficult child has flat earth thinking. Once one step is done it's as if the rest of the task falls off the earth. No continuation or initiation of the next step.
How about adding "Do step 2" to the steps?
As for when to start life skills....Looking back, I guess I started without difficult child OR me realizing it. If we went shopping for something in particular, say school clothes for example, I would herd difficult child towards clearance racks first. Yes it was always in my head that he needed to understand that money doesn't grow on trees but mostly that was just due to household finances and my own cheapness! LOL He didn't take long to pick up on that one and now will head directly for the clearance stuff when he's looking for something. (He once found an awesome down coat on clearance at Wal-Mart for $30!) I think part of that is just simple greed. He's figured out that if we only have a certain amount to spend, then he can get more stuff if he finds what he wants on sale. Another thing I did when shopping with him was explain why I wasn't willing to buy X for $60 when we could get Y for $30. I don't mind spending a little more on clothes or shoes for him if I'm getting a better quality. But if he's in the middle of a growth spurt, I'm not spending more money on something that he's going to outgrow in a month and he has pretty much understood that since we got him. (Doesn't mean he likes it, just that he gets it)
Now he's 17 and needs to start learning more than he does. Our problem with him is that he has the typical teen thinking of "Mom and Dad are stupid" except that he applies that to EVERYTHING. If I tell him that he can't use CLR to clean his shoes because it's caustic, he'll do it anyway because I don't know what I'm talking about and it won't hurt anything. Uh-huh...that's why I need a new bath mat....he burnt a hole right through it with the CLR.
You said your difficult child is 13. I would start with what you know she can handle. Helping with meals, at the grocery store (like someone else mentioned....which is the better deal, we want this but how does it fit into the budget, etc. Coupons are a good way to start out with this too.) If she's not ready to do laundry all the way through, teach her to sort out her clothes for you or take stuff out of the washer and toss into the dryer. I would just start her out on things she needs to know anyway but start small (or whatever she can handle). If she can go off of written instructions (sort laundry, put a load into the washer, make sure it's set on appropriate settings, add soap, turn on, shut lid) do that. If she needs to see the instructions, show her or even take pictures (Picture A is the level where your clothes should be in the washer-without water- to make a full load, picture B shows where the knobs should be to wash a load of darks, etc.)
You know her best and know what she can or can't do at this point. She's old enough to start with things. Some of it, too, you can slip in and she won't even realize she's learning. At her age (non difficult child but still), I was cooking full meals, cleaning the house and doing laundry. And at 16 I would be handed a grocery list, coupons and a certain amount of money. I had to get everything on the list with the money that I had. If I had extra money, I could pick up a treat. We all learn at different ages but start now. It may not sink in for a few years but at least then you're that much ahead.