agreedIf you are positive about 8 weeks of age, then that is a rooster.
Hens only get comb growth and reddness just before point of lay, which can vary, depending upon breed, from 18 to 24 weeks.
Since your bird has a large red comb now, and is around 8 to 10 weeks of age, it is a rooster. Roosters get red combs early. Depending upon the breed, roosters can show a red comb at 4 to 10 weeks of age...at any rate...if you get a large red comb sometime before 10 to 12 weeks of age, you've got a boy.