You have a 5-year old Instagram account which you have been using to post pictures from your personal life and the food you eat.
You have over 2000 followers there, mostly friends.
You got an awesome idea to make a course and promote it on Instagram.
Wow! What a profitable thought.
But, you started promoting this on the same account you were posting vacation photos and tasty food!
And you mix these 2 types of content - photos from your life and content related to your course.
Having 1 account for more than 1 purpose is going to take you nowhere, you won't achieve either of the purposes.
If you want to start promoting a course, create a new account for it and post only educational content and promotional content related to your course there.
You can create a new account as a business or even as a personal brand (which is even better).