Get used to it. Folks judge based on age and gender and race and the rest. They like to hear themselves talk. They like to know more than the next guy.
I had a student once who was teaching others after literally 15 minutes on the mat.
When people talk at me on the mat I abruptly shush them. It's rude on both counts, but they drew first blood.
In turn, I only offer suggestions when asked, and sometimes not then. You might try this, especially at 3 KYU.
"Underestimated." Who isn't? Who cares? Who should?
You're paying attention to the wrong things.