@vette98, The Parkinson's Foundation has some helpful information for learning more about the stages and more - https://www.parkinson.org/understanding-parkinsons/what-is-parkinsons/stages.

You might also want to connect with others and learn what they have shared in the different discussions on Parkinson's here on Connect. Here is a list of the different discussions - https://connect.mayoclinic.org/search/discussions/.

@vette98 This is what the Mayo Clinic says about Parkinson’s Disease: https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055 The Mayo Clinic doesn’t specify stages in Parkinson’s disease mainly because so many patients are so very different. Especially when you compare young-adult onset with those who demonstrate symptoms late in life.
I would suggest that you look up The Parkinson’s Foundation (organization, association.) to get more information.
The stages of Parkinson's disease progress differently for each person. Additionally, patients may have good days and bad days with symptoms resembling different stages. It often takes 10 or 15 years for a patient to progress to stage four, however many do not progress beyond stage three.
I hope this will help.