Girls: cute way of asking a girl out?

So my ex and I have been talking alot lately and I decided to ask her to prom. I was thinking of dressing my cute 3 year old nephew dress up as spongebob (her fab character) and record him saying "Iiiiiiiiiimmmmmm reeeeeaaaadddyyyyy for you to go to prom with John" is that cute or stupid? Should I go with it or no?