Since it’s an online course I would like you start with sales funnel, which comprises of ads, landing page, sales page, an email campaign.
It will help to circulate the online platform, and I will write any copy for you.
The copy must come with a good educational idea, that will grab the attention of any person that comes across it.
The educational niche need to come in educational way starting with things they supposed to know as a human, because even the young and the old can be part of the online course right?
So for the young, they have to know the reason why they need solid education, and for the old they have to be motivated, telling them that they can accomplish their dream not minding their age.
Lastly you have to make availability of free stuff like introducing the course to them and telling them few things that they will be happy to hear (this will be in the landing page description as free video that will drive them to your website), it will be a kind of video, I will rather tag it “unique idea you don’t know about this online course ( you should add the name), it will motivate them to read. I can equally write the VSL for you.
I believe I have given many point you can work on, you can message me for more help