Is this a good idea to do with my girlfriend?

Well we will have been together 3 months on thursday, and we have never done anything super special that she wasn't already expecting...so! I was thinking, we could drive up to the place I first asked her out, which is this cliff overlooking the city I live in. She would just be expecting us to chill in the car...but my plan is to go into the trunk, pull out a boquet of flowers, and put on either a Sinatra song or Bye Bye Blackbird (she loves both) and ask her to dance with me up there. So I was just wondering if you thought it would be a good idea? Thanks!