Hello!
I have two Etsy shops and have been running one of them for almost three years. I can let you know about my situation but don't want to give Official Legal/Tax Advice ;)
From my understanding, you do not NEED to register to collect HST until you have sold at least $30,000 over the course of four consecutive quarters. I did have to register for one in 2016. You CAN elect to register for one at any time, since you "get back" the HST you spend on supplies. I sell a lot internationally and do not collect HST from them, but do buy many supplies in Canada, so it tends to even out for me.
https://www.canada.ca/en/services/taxes/gsthst.htmlIf you have any questions about Etsy stuff I'm happy to chat. Both my shops are niche jewellery shops. I like to think I am fairly successful, and only run the shops as a hobby/side hustle (for now - not going to be quitting my day job anytime soon!). I always warn people that the business side to running a creative business takes WAY more time than you'd think, especially as you're learning!