Tell her you want to support her in her old age in the manner to which she would like to become accustomed (oh, say, a queen
) and that the only way to do that is for you to become technically proficient as a computing expert, even if it's only part of being an expert in other things (a writer, in marketing, via artistic endeavo(u)rs, etc). I'm actually being quite serious - I'm not only a practi(c/s)ing computer scientist and software engineer, but also a STEM teacher, former military officer, an airplane and helicopter pilot, nuclear engineer, amateur musician, writer of horribly-long forum posts and e-mails (aka a latent author), photographic and videographic enthusiast, and probably half a dozen other things that I've spent less time doing than the others. As a result, I've never been at a loss for being qualified for whatever work has been available.
It's predicted that students graduating from secondary school today will have an average of eight career (not just job, but career) changes during their lifetimes, and much of that will be due to technological advances. Ten years ago, there were no such jobs as tablet app developer, search engine optimization engineer, or mobile content artist, yet they are some of the best-paying jobs available, and many of the skills can be learned on your own via on-line sources of information. Education is being turned upside-down and inside-out via remote/distance-learning technologies as institutions turn to video teleconferencing, class forum chat, and development and delivery of lessons that are self-paced by the student. Progress can now be tracked individually by the student, educators, and parents down to single questions and answers, and the same material can be covered in multiple ways until the student finally truly grasps the intended lesson.
Work is returning to industrialized nations' factories not in the low-paying jobs that were sent overseas, but in the form of operators and technicians who not only keep automated robotic machinery going, but enhancing and expanding it. There is a crying need for computer numerical controlled (CNC) machine operators and maintenance people in every manufacturing area, and as use of robotics continues expanding (used to build our Pi boards, BTW), the demand for people with the skills to install, maintain, and repair them will continue to grow.
You can't walk into a semiconductor fab nowadays without at least a two-year degree in industrial or electronics technology, and the same is going to be true for virtually every factory by the time you graduate from secondary school. The days of getting a general education and then getting hired easily are rapidly dwindling - if you understand computing and are competing for almost any job, you will have an enormous advantage over the competition.
Even if you wind up becoming an accountant, you'd better understand how to use forensic accounting software to help spot fraud and other criminal activity, because criminals have discovered that most money is now handled via computers. $40 million was just stolen via ATMs because criminal hackers were able to defeat not highly-regulated banking software, but unregulated credit card processing software. They hacked the credit limits on cloned credit and debit cards to tens of thousands of dollars each, and then had runners literally hit dozens of ATMs each within a span of less than an hour in a number of major cities. Do you think those credit card companies are going to be hiring more accountants that were clueless about this kind of operation, or those who understand how to develop software to detect and prevent such activity in the future?
There are tens of thousands of examples of other jobs whose descriptions are going to include the words software, computing, digital communications, etc., in the coming years. The $25/$35 cost of a Pi is going to seem like the best bargain of all time when you're able to parlay it into work worth at least high five figures, and probably low six figures by the time you're ready to join the work force after you finish your education. Tell her about the 17 year-old lad in London who taught himself programming starting at age 12 and just sold his Summly app technology to Yahoo for $30 million, along with a nice desk job in Yahoo's London offices where PhDs will be working for him to help further improve his technology ... after he finishes his secondary school studies! Yahoo also just bought Tumblr for $1.1 billion from a high school dropout who started the company rather than spend any more time in school (that's a very risky move and you need to be both brilliant in software development and marketing, and extremely lucky to be in the right place at the right time in order to pull something like that off).
I was told in 1977 by a professor that, within 10 years, there would be two kinds of engineers (I had just earned an engineering degree), those who understood computers, and those who would be unemployed, and he was exactly spot on in his advice (I earned an MS in computer science a few years later). Now the same is happening to virtually every other job in the world beyond the most mundane manual labor in fields and rudimentary manufacturing (there doesn't seem to be much of a life in being a garment fabricator in Bangladesh, does there?). It's now becoming cheaper to use robotics for manufacturing than even the lowest-paid foreign factory workers, because robots don't complain, get tired, need breaks, make many mistakes, need medical/dental/optometry plans, go on strike ... are you seeing a trend here? We can use robots more cheaply in our own country and not have to deal with weeks of surface transportation delays in bulk shipment of parts, subassemblies, and finished products - assuming it's all 100% defect-free, which it won't be (ask the Foundation about its issues with its first Chinese manufacturer substituting an Ethernet connector that caused failures with longer cables).
Welcome to the forum, and tell your mum we said she needs to get you a Pi now
before one of your future job competitors does