I got offered a career in my senior year of college...Help

I am completing my final year of college, and a principal on Linkedin reached out to me. He asked me would I like to be interviewed for the position of librarian at the elementary school he is the principal at. I was a library associate 2/children's librarian at my local public library for almost three years. I major in professional writing (which is a type of English degree), and I am minoring in communications. I am in an honors society, and I don't really have to be involved. It is a lifetime membership. But, I graduate in December of this year. I decided to complete senior year without working, although I worked full-time the previous years. I am kind of nervous to turn down this opportunity. But, I am also nervous to accept it as well. I feel underqualified because I am nervous. But, I also don't know if I should say no or not. What would you do? And does anyone have any advice? I have not responded to him yet. He sent it yesterday. I am still undecided. Please help.