Quick idea for film opening

I have come up with an idea of how to introduce a character into the film opening that we are creating. For the girls friend that is one of the main characters, I thought it would be a good idea for her to be seen for the first time at the picnic that the main girl is heading for whilst travelling on her bike in the first 38 seconds of the film opening. As the main characters shakes out the picnic blanket to lay it out and drop it, the girl will just appear as the blanket is laid down in slow motion. This will make her appear as a ghostly figure as she just appears unexpectedly and this is the aim that we are going for.