No, but you need to approach the craft as if you're earning a degree every day. It is highly recommended to have a high school diploma with English credits as it provides a solid foundation in grammar and mechanics, greatly assisting you on your writing journey.
Unlike some professions that require certifications, writers only need to demonstrate their work for a chance at success, even if they have been writing for their entire life.
One thing that many writers overlook as they grow older is the fact that writing is a skill that must be continuously cultivated through studying books, participating in writing workshops, sharing work with others, accepting critiques, and applying the lessons learned from those criticisms. It is also important to submit your work to editors and be prepared for potential rejections.
Become well-versed in the language of authors so that you can engage in intelligent discussions about it. Master your primary language and familiarize yourself with the vocabulary used in fiction writing. Explore important concepts such as conflict, character development, motivation, and conventions.
Learn about the business side of writing, including how to write effective queries and pitches. Attend writing conferences and join writing groups to immerse yourself in a community of fellow writers. Surround yourself with writers whose skills and abilities you admire, and learn from them.
A formal degree may not be necessary, but you should approach the craft with the same level of dedication and focus as if you were pursuing a degree throughout your entire life.