The upgrade process is very straightforward if you haven't made any changes the default theme as it's as simple as uploading and activating the new version, but
if you are planning to customize it we would strongly recommend the use of a child theme to minimize the loss of your modifications in the process of an upgrade. Version 1.2 has a number of new features as it is a major release, and since it's not too far away you may wish to wait for that before starting and then having to make changes to suit the new version, however that's entirely up to you. Thanks.