Is it possible to change the sequence of convolution layer and pooling layer?
In crude terms, a single convolution layer tries to capture to what degree certain feature is present in given region of figure. Max pooling layer is a downsampling strategy: instead of capturing presence of certain feature to a very fine-grained degree, the layer downsamples to certain classes like almost present, almost not present. (In crude terms because what exactly each layer learns is highly specific to dataset and network architecture used).

If you think of convolution as signal extraction and max pooling as a downsampling/smoothing strategy, it makes sense to use smoothing after signal extraction and not before.