I know more under-25 Rebeccas and Rebecas than older ones, but don't really think of it as 'a 90s name', because it's not uncommon on older people too. I like it, it's somehow quite fancy and lush without being frilly. I've seen a few Welsh
BAs for just Beca fairly recently: that and Becs seem more common as an nn here than
Becky.