I’m about 30 and still skinny. I eat at least 2,000 kcal a day, up to 3,000 kcal. I only get more weight by working out. Recently I’ve been injured and couldn’t work out for several months. I dropped back to about 70 kg (I’m almost 1,90 m) - while eating the same amount of calories.
Maybe I need to space out my calories, I only eat two meals and don’t snack at all. These just happen to be really big meals.
For the record, I’ve been checked for thyroid issues and other stuff. My body just really wants to stay at 70 kg, I guess.
10 years ago people told me the same thing about getting 30, yet it still hasn’t happened. Whether that day may come or not, I can just appreciate that I still get “Once you’re old…” kinda stuff after 30. Feels good, actually.