My 3yo and all her friends are obsessed with Frozen. DD wants to be Elsa when she grows up. Every one of her possessions would be Frozen themed if I'd let her get away with it. It's everywhere, and it's persistent- even though the film was a good while ago.
There are also a lot of Ella's and Islas (different pronunciation but visually similar) in that age group just now.
Let it go.
Unless you are actually intending to name her after Queen Elsa, who in fairness is pretty amazing, in which case absolutely, crack on!