Coates, 25, became one of the youngest ever managers in the women’s professional game when she stepped up from her role as assistant first team coach to replace Glen Harris in June.
She was unable to turn the tide, however, as the Belles were relegated from FAWSL1 after one season back in the top flight.
Doncaster finished the campaign with just three points to their name and a goal difference of -40.
Coates said: “I think all the backroom staff, those that go unnoticed, have given me a huge amount of support and, at times, I’ve needed it. I’ve gone to them and asked for advice and they’ve given me more than I could ever ask for.
“I feel like I’ve let them down, if I’m honest, but they’re fully behind me and work has already started for next season.”
She added: “We’re already in the office all day, every day, to make sure we get things right for January and those plans will be strong plans.”