Yes, you are able to reorder your Practice Blocks.
When inside a Practice Script, simply navigate to the "Reorder Blocks" button in the upper right corner of your screen. You then can click and drag to reorder them. Click the button again to save any changes.
Keep in mind, you can still switch between blocks freely while on the field using the GoRout Practice App. Changing the order of the blocks on the desktop will just set the default order.