Wordpress website doe not use www. Is this a problem for seo?

Hello, Started up a new website as a hobby. I'm not much of an expert but have some experience.

Anyway, I have noticed that my sitemap has stopped updating. I also noticed that my website does not have www. in any of the urls? Is this an issue and have an impact on SEO? and I'm not sure how this has happened. About half my website shows up on google but the sitemap shows last updated on 4/24/21.