It's funny how the mind tricks us, or them
This can be a very tricky situation. Sometimes either we have the wrong idea about our attitudes or other people simply perceive them differently. The only way I can clarify a situation like this is by simply reflecting back on exactly how I reacted and what I did. Then I simply brainstorm if there was a better way to handle things.
I am hoping the certain person and their mom come to a mutual understanding about you and hopefully it can avoid future possible cases of miscommunication.