Is my KLWH math right for my solar setup?

I have 3 120watt solar panels hooked into a 360watt grid tie inverter. if electric is about 12 cents per kilowatt hour and if i run it for 7 hours a day then .360 times .12 is .0432 cents an hour. times 7 hours a day is 30 cents. times 365 days in a year is 109.50. so, assuming i get full sun for 7 hours everyday ( which i wont haha ) then i'd save 109.50 a year right? my system costs around 1300$. so in theory if i got full sun it would take 11.87214611872146 years for me to make my money back. Is my math right lol?