The phrase "am out of line" implies that someone is not behaving or speaking appropriately. A few possible antonyms for this phrase could be "am in line," "am on track," or "am behaving appropriately." These antonyms suggest that the person in question is adhering to an expected standard of behavior or speech, and is not violating any social norms or conventions. Additionally, antonyms like "am respectful," "am courteous," and "am polite" convey that the person is showing appropriate manners and consideration for others. In contrast, the original phrase "am out of line" suggests that the person may be rude, disrespectful, or inappropriate in some way.