Second, about your small belly, ordinary sit-ups are useless to you at all. You should suffer more. When you go to the gym to exercise, let the coach watch over you. The specific method is: tilt-down sit-ups (refer to the exercise method of Tony Jaa, Thailand's top kung fu emperor (he does tilt-down sit-ups with an 80kg barbell (ordinary people can't reach this quality at all))-I suggest you sign up for a dumbbell tablet of10-20kg, put it on your chest, and then, set 20 pieces, and each group will get up and jump immediately after exercise (aerobic at this time). Just stick to it three times a week.
Third, finally, I would like to remind you that abdominal muscles are the most stubborn muscle group and need continuous stimulation. Maybe you have been crazy for a week. If you relax immediately, the lines of your abdominal muscles will soon become unclear. Especially the small belly will start to bulge, so persistence is victory. In addition, it is best not to eat supper. If you are really hungry, drink a glass of milk and chew some beef jerky before going to bed (a small amount, lean meat type). According to the rules of many famous senior bodybuilders, they should do at least 100 sit-ups before going to bed every night. If you think it is helpful to you, please stick to it!
When you want to give up, just look at Ronnie Kalman, Arnold Schwarzenegger, Joe Kate and other strongmen to encourage yourself and stick to it!