Your work is very beautiful, and I think it is definitely commercially viable, and you could make a business from it.
I've been a self-employed artist since I was 16 years, and the best advice I could give you is to be absolutely passionate about what you do, because people will respond to that and your work will be successful.
Having said that, it is necessary to find a market for your work, and I wonder if you have looked into Etsy to sell online? Customers love to buy personalised things, and your calligraphy would be perfect for that! You could design personalised wedding invitation, birthday cards, engagement notices etc.. try browsing Etsy for artists who are doing similar calligraphy as you to get some ideas.
All the Best!