You're never too old for a bit of Disney. I have a few favourites, but if I had to pick my ultimate it would probably be The Little Mermaid. I wanted to BE Ariel when I was 5. Hell, nearly 23 years later, I still do.
So when I was browsing ebay for nail art supplies and came across some Disney-themed nail decals I had to get some Ariel ones. I actually got these sometime last year, and can't seem to find the seller. But there are other similar ones available.
I'm still in awe of my Jessica Hologram Chic nail polish. It's difficult to capture how pretty it is. I added some block colours and dots using Models Own Apple Pie, Blooboo and Utopia, with Ariel on my ring finger. The decals are applied by soaking in water for a few seconds, slipping the transfer off the backing and then placing on the nail. Wait for it to dry (it can take a while, but it leaves you ages to place it exactly where you want it) then apply a top coat. It's so easy. I find water decals a lot easier to apply than nail wraps.