Some diamond stud earrings, a gold link chain or a watch would probably make most sense
either they'll be worn and broken/lost but get some use or put in a box somewhere and rediscovered when they're older. In years to come "yeah, I remember that for my 18th I got a pair of diamond earrings/gold necklace" is probably a good thing to recollect. Better than "yeah, I got a sensible winter jacket." but then what do I know.
( garold you're on mute I SAID YOU'RE ON MUTE, Tue 2 Feb 2021, 9:08, archived)

^queer eye for the web guy

( Queef Smegwin U r a 🔔🔚, Tue 2 Feb 2021, 9:09, archived)