According to the current information plans of the Home Office, if you finish the course before 2020, you will still benefit from the same working regulations as EEA citizens do now.
As of 14 January 2019, the current information of European citizens in the UK following Brexit is that for EEA citizens, the same right relating to working in the UK will be upheld until December 31 2020 as they are now available in pre-Brexit UK, meaning that EEA citizens will not need working visa.
If an EEA citizen has pre-settled status in the UK, their right to work remains the same as it was in pre-Brexit UK for five years after securing their pre-settled status. To learn more about pre-settled status please see here: https://www.gov.uk/settled-status-eu-citizens-families