There are things i can think of that you may try:

1. Try and do something techy yourself. Getting your own hands dirty will give you much better insights into what she’s getting into. Something that’s useful to you. I don’t know what you’re into, but if you have a hobby, it’s usually easy to find an idea for a tool that will help with that hobby. Just make sure you don’t try and take her place or something.

2. Probably better: Ask HER, if she could make something useful to you, or even better for your whole family / community. You may go for something a little more complicated, cause she’ll have more time to devote to this. IoT projects are very rewarding and touch a lot of aspect of tech. Home automation projects are great, like connected lightbulbs that respond to voice or if you have emails. Small games like wordle are cool too. Or things like community websites. When I was 18 (22 years ago!), I built a message board for me and my friends. It was really fun and then i could customize it for things we liked to do, like rating movies, and plan holidays. We used it for years, and only stopped when the ISP stopped supported the backend tech I was using.

In any case, the sooner she starts the better off she’ll be. The first thing is to pick up anything: a book or a tutorial online, and give it a shot.

Good luck, and have fun!!