Gst on online educational courses

Hi experts,

I run a blog and a YouTube channel. My revenue is less than 20 lacs. Most of the sales are interstate. I sell my courses directly to my students. 

Types of products that I sell :-

1) ebooks (Sold online on my blog)

2) Pen drives

3) Online courses

I have applied for GST number but I am not sure whether "Educational services" are exempted under GST or not. Further, whether I need to collect GST even if my revenues are less than 20 lacs.