When going green to gold, will I have a 6-8 year military obligation after already having completed my 8-year obligation enlisted?

The clock starts all over from scratch and nullifies the remainder of what your enlisted obligation was.

You will have an 8 year obligation given there are three options to get the degree will probably determine the amount of active time you might have to serve. Here is a link to down load the PDF file with info.

https://www.goarmy.com/content/dam/goarmy/downloaded_assets/pdfs/gtg-ado-application-booklet.pdf

And here is a link to the website to explain the 3 options.

https://www.goarmy.com/careers-and-jobs/current-and-prior-service/advance-your-career/green-to-gold.html

That depends on how many years you are in school and which G2G route you take. Anywhere from 4-8 years would be the commitment for G2G and no guarantee you would be commissioned onto Active Duty.

However, it begs the question of why you would wait six go eight years to go to college when you could easily finish a degree on AD in that amount of time