You can eat meatballs when you go to your boyfriend's house for the first time. There is no custom, or it is stipulated that you can't eat meatballs at your boyfriend's house for the first time. If you like meatballs, eat them to your heart's content; If you think meatballs are too greasy, you can choose other dishes.

Besides, when I go to the man's house for the first time, it must be his parents who cook. You like eating meatballs, which shows that their parents are good at cooking. They will be happy to see you eating so happily.

So don't worry too much about eating meatballs. Eat if you like, and don't eat if you don't like. It's up to you.