When I was 25, I could have gotten away with eating breakfast 2.5 hours before a race. Now I'm 45 and all that food will still be sitting in my stomach in 2.5 hours.
I get out if bed fours hours before race time and eat a bagel with cream cheese, than drink some coffee so I can purge last night's dinner from system.
You know your body better than any of us. How long do you feel full after you eat? A little longer than that is how long you should eat before your race.
And fuel isn't much of a factor in a 10K, if you're not starving at the start line, you'll be fine.