Someone said it depends on lightness or darkness of skin but I think undertones matter more, just as it does for jewelry or makeup.
I am a very pale natural redhead but have “warm undertones” and the gold looks much nicer on me as does gold in general. A cool silver looks cold. Someone with much darker skin than me or who is tanned may have cool undertones and look much better with silver.
I do mix and match gold, rose gold, and platinum jewelry a lot - as I type this I have a yellow gold wedding band and a platinum diamond ring on - but I went with what looked best on me “on its own” and caught my eye the most since I am wearing my watch almost all the time.
I think lots of band colours look surprisingly awesome with the gold; it really can shift from more pink to more a soft copper depending on what you pair it with band-wise. I personally love the combination of the gold with a black band (any material) most of all and would have gone with the gold AW just for that combo alone. I have a third party black sport loop that looks amazing as it has pinkish flecks in it. But I also wear it with whites/ivories, greens, various pinkish shades, browns, etc all in all sorts of materials. Blues - especially deeper purplish blues IMO - look amazing with the gold (like Indigo) and red is a bit more unusual choice for some I suppose but looks good especially if she has the cellular version with the red on the dial. The only colour bands I don’t really wear it with are...silver. Ha.
I think teenagers tend to be a little more expressive in colour anyway these days even if they don’t “match” (when I was a teenager - way before smart phone technology - only black would have been acceptable being my grunge and goth days).
She can always exchange it if she does not like the colour so really, you can just buy either and let her know she can switch it.
Lucky girl whatever colour; I know for sure my grade 9 graduation did not come with any gifts (except the gift of moving to grade 10 I guess!).
