Was I unfair to start dinner when my friend was late again?

At seven-twenty, I ordered while my friend was still on her way. We'd agreed to meet at seven. When she arrived at seven-thirty-five, my food had just come out. She said, "You could have waited for me."

Usually I do. She's late often enough that I bring a book, and she always apologises warmly. This time I had a class afterwards and didn't want to rush my meal. I'd texted at seven-ten to say I was going to order, but she didn't see the message until she arrived.

We had a decent catch-up, though she kept saying it felt strange to sit opposite someone already eating. I said I'd be starting at the agreed time from now on. She called that treating our friendship like a work meeting.

I don't want every dinner to begin with a lesson about punctuality. I just want to eat without calculating how much of the evening will be left. Was the way I handled it too abrupt, even if the change itself is reasonable?