Freelancing nature photography

Hi there I am a woman who takes many nature photos. I dont take portraits because I have no one to take portraits of and I have some social anxiety you see. My family thinks I should freelance my photography for sale because I am good at it and because the local newspaper has featured several of my photos on their instagram page. I studied photography in school and I have a degree but I never considered working in photography. I am trying to find employment at the moment but not with photography because the competition is too high. I have one very old system camera from 2008. I think it is really good and I am only missing a zoom lens which I am planning to buy. I would really like to take better pictures of, specifically, various kinds of birds. Anyone here have any experience of this or freelancing in general please? Do I only need to buy a domain and make a portfolio-website for myself and do you think I need to have a physical portfolio?! I would love to have a physical porfolio but.... I dont have a printer or can afford to print many many photos at this moment... Do nature photography sell?! Who buys?!