I hope that you are keeping a list of the + & - of both options. I did 8 years and decided that I didn't want to go back out to sea. If you are in the service, you have to go where they tell you. After 20 years, you get to retire, draw a pension, and still keep some of the benefits of the military. Are you willing to endure 12 more years?
If you decide to get out, the starting pay at a power plant is usually a bit on the low side, around $30/hr+ or -. With overtime, 80k/yr is easily obtained. After 2 or 3 years, the pay rate should be in the uppr $30s. With OT, $120K/yr is esily achievable. That is like 300 - 400 OT hours/yr. Most places have benefits - pension, medical, vision, dental, vacation, etc. Training, engineering, and admin generally don't get any OT and salary may be $80K-$100K/yr
Of course, OPS is on shift perpetually. Maintenance is on days with some nights to support backshift work. Then there is outage time every 1 1/2 or 2 years. Then everyone works 12 hours/day, 6 days/wk. Half the crew is on nights.