Is it normal for someone in a new workplace to dismiss you on first meeting?

It was my third day in that new workplace. It was the first time I had spoken to her. I didn't even know her name or what she taught, though I knew she had some kind of admin function in the school besides teaching, and she was using it to make changes to my timetabling.

It turns out our ways of teaching a certain course are different and she thought that that meant I was doing it badly. I have not got as much experience as some, and she pointed that out to me, but I have done that particular subject before in another school and I was proud of what I achieved with my students, and so was that school. My willingness to teach it was actually part of why I got hired here.

I tried to explain to this colleague how I respected the objectives of the course while doing it in the way I did it. I didn't do that because I was determined to convince her to let me have my way with this year's teaching groups; I was more affronted by her unfounded judgment of me and was concerned to show her that she was mistaken in treating me as inept on first sight. When I tried to explain though, she just interrupted me as I spoke and told me to speak to my more experienced colleague.

I was like WTF? I don't even know your name and you don't have a clue what I've done or what I can do, and you're completely dismissing all time and energy I put into my course design last year in order to make sure it worked, when YOU DON'T EVEN LET ME EXPLAIN WHAT THAT DESIGN WAS?

Is this normal? Am I the asshole? Can anyone provide perspective? Mostly, I want to understand what might have been going through her head.

For the record, she seemed to be culturally Asian - maybe Korean. I have had issues with dismissive Korean colleagues before and I don't want to dismiss her as 'just one of those dismissive Koreans', but if it were a factor, I'd feel better for understanding as much.