I'll second Lisa's recommendation to set up on Goodreads. You can use it as your pro writer's website AND a social media presence whereby your readers can ask you questions and you can answer them. For an example see the one by Lois McMaster Bujold, one of the most popular sci-fi/fantasy writers. Among other benefits, it lists all her published books and shows their ratings, which in Bujold's case are (surprise!) all in the near-five-star range. For comparison with a newly published Goodreads writer such as you would be see my Gr page. Notice that on both sites there are links to your Twitter, Facebook, and so on accounts. There is also a link to any web site you may have.
https://www.goodreads.com/author/show/16094.Lois_McMaster_Bujold
https://www.goodreads.com/author/show/6490844.Laer_Carroll
For a more flexible website you might want to add (not use as a substitute) one based on WordPress or Blogger. I recommend WP for a variety of reasons, which you'll find here:
https://en.wordpress.com/features/. It's totally free, though you may want to splurge $18 a year to rent a custom domain such as YourName.com. Try to pick a domain that includes your pen name, as it makes it easier for your readers to find your site. If .com is not available try .net, .org, .info, .me, or other low-cost options.
You can start a decent-looking web site for just a few minutes work, then over time tailor it to a unique brand for all your current and future books. There is an art as well as technique to creating a site. It also takes time to build up readers; it took four years for me to get a mere 212 followers. TAKE BABY STEPS and KEEP IT SIMPLE. Your job is to write stories, not build sites or write blog posts.
If you do blog, I'd suggest you post once a week on average, SHORT posts, on subjects you're passionate about. For those subjects you probably discover some new event, book, movie, TV show, or web article at least that often which you would like to share with your prospective fans. Thus you don't have to struggle to come up with subjects to post about; they pop up in the normal course of your life. Those subjects will likely end up in your books, and will also interest readers who are likely to enjoy your books.
WordPress, and to a lesser extent Blogger, allows your site to be both a blog (which on my site I label News) and a static, or rarely changing, site. In that part you can add info such as backgrounds of one of your books or series, genealogies of main characters, lengthier articles about whatever subjects which don't usually belong in a blog post, a bio, and so on. Remember, that material is something you can build up over time, not in one quick marathon of activity.
Finally, with Fruitbat I suggest you simply set up a web site and give the agent a link to it. But I'd NOT add that it's a new site or apologize for it in any way. The unspoken info you want to pass on is that "Sure, I have a site. Here it is."