I did the same thing to my instructor. And most of my students do the same to me. It's just par for the course when you're learning.

Here in Oklahoma we live with pretty constant wind like you do too. I would say for a beginner 10-15 mph would probably be too much. But it really depends on a lot of things. 20 mph straight down the runway is a lot easier to deal with than a 10 mph crosswind at times. Things like this is why the instructor is having you call, because there are times that you can't judge just by the wind speed.

Ken