Legally File for a Business or Buildup Social Media – Which First?

I am just at the beginning of opening my coaching business. I went through all of Brookes Entrepreneur material including the bookkeeping. However, I’m unsure of what my niche will be. I want to be more general and then see what speaks to me.

But since I’m in explore mode I’m wondering if I should buildup my social media presence like Youtube, Instsgram, etc and see what people respond to THEN legally create a bussiness like file for an LLC,etc

OR if I should create an LLC, website and all of that first but I’m unsure what I would call the company or post on the website since I’m still exploring my audience.

Any help would be so so phenomenal!

Thank you all for all you do!!