I think it's a good plan, but I do have concerns about the implementation, because I get the impression that it's been pretty much landed on schools without much (any?) training.
I've been working in IT for over 15 years (how did that happen?) I'm also a StemNet ambassador. It's not where I started off - my first degree is history, and I think that adds to my role, because I've got a broader outlook and better written skills than many of my colleagues.
I went into IT partly because it was like learning a new language (I enjoy learning languages.) I was surprised I found coding frustrating - spotting syntax errors and so on; in written text, I can spot a misplaced apostrophe or similar whether I look for it or not, and I have a tendency towards pedantry, so I expected to find it easier (Muphry's law means I will now have peppered this post with errors!) I'm now a unix sys admin, and I usually get other people to do scripting (which is coding/programming for the unix operating system,) but it's certainly useful to be able to read code, and I wouldn't be able to do my job properly if I couldn't follow a script.
IT is behind almost everything we do these days, so it is important to have some understanding of how things work, from the architecture of computers, to how we make them do things - with coding. It's important to understand the logic of algorithms, even if you don't know the metalanguage for it.
Most of us will have used basic algorithms, whether we know it or not - it basically means procedure, so recipes are algorithms. Knitting patterns are algorithms; if you can understand a knitting pattern, you can understand most of the basic logic of programming. Where it tells you to knit until the work measures 20cm, that's like a while loop (while work does not equal 20cm, knit row, measure work; then loop to start of statement, so you repeat it until the work does measure 20cm, and then you move on to the next instruction).
If people don't understand how IT works, they're putting themselves at a disadvantage. IT controls most of our world these days, and everyone should have the opportunity to learn the basic understanding that will mean they can be part of that - and that definitely includes girls. I'm the one woman in a department of 40. All the programmers up-thread have said they're the only one. We shouldn't be in such a minority, and we shouldn't be letting men have all the power (because some of them are pretty bad at it, though of course if you get more women, then some of them won't be so good at what they do, either.) It can be well-paid, flexible (hours, ability to work from home), and interesting - there's such a variety of roles. It should be an ideal career for women - why aren't there more women doing it? There's a whole range of reasons, and a lot's been written about it, so some of the answers are out there, but I think we can change it.
I think getting children involved in understanding the logic and so on is a good thing, and if everyone's doing it, then girls are less likely to come out thinking, "it's just for boys". I really hope that teachers get the support they need for this to work well.
(I know this is a long post, but I've actually been quite restrained; it's something I'm feeling more strongly about with every year that passes.)