Birth plans are great for birthing mothers and their partners to let us midwives know what they would like to happen during their birthing experience. Please keep it in the back of your mind that things don't always go according to plan and the midwives and doctors may not be able to met everything on your list for medical reasons and/or emergencies. Speaking professionally we (midwives) do our absolute best to ensure that we do everything you want for YOUR birthing experiences but sometimes circumstances do prevent us.
Most definetely have a birth plan, they are a wonderful tool, but also keep an open mind so that you are not disappointed or shattered if your birth does not go according to your birth plan.
I've got mine started too but it still needs some fine tuning.