If you are going to use traffic light colours to indicate project status you probably want to start red rather than end red. Here is the justification.
Most projects don't deliver on their promise.
Call out industry reports which show the rate of fails, challenged, over budget and schedule, etc. Go wider than the Standish/Chaos report. There are plenty of alternatives that tell similar stories. The best evidence comes from internal records. Check out the last 5-6 projects of a similar scale to yours. Have a look at the initial planned budget and the actual budget at completion. The put it in a slide deck.
Project Management Can Help
When I was doing my formal project management studies I cam across a number (which I can't recall, but may have been about either 30% or 300%, the source was a PMI Turner) that described the typical benefit project management can bring to <ahem> chaos.
Project Management is important but insufficient
You also need three other things to make a project work. Without these three things you are guaranteed to run into troubles. They are
- Support from a sponsor that understands the project and is prepared to roll up their sleeves when necessary,
- A Team who have sufficient technical skills and can work together as a unit,
- Stakeholders that are informed about and aligned to the project goals so that they understand how to manage user requirements and to work with the project team to fulfil the sponsor's goals.
So, based on the evidence you have today what's your current project status? Until each of these criteria (plus any other local issues you have) are addressed and tested you are in the red.
Start a project in the red, know you are in trouble and manage your way out of it. It's much better to work this way than the other way around.