Ted here from Shopify, thanks for reaching out to us!
This is a great question! Our Support can add this to your account but I can see that the trial was already added by my colleague a few days ago. For anyone else reading this too, if you would like a 90-day trial extension our Support will need to add this manually for some accounts. Please contact our Support directly here for assistance.
Your site looks like it's really coming together! Before you are ready to launch, I'd for sure recommend asking for some store feedback in our Feedback Forum when you are ready as fellow merchants, experts and developers hang out there and are happy to offer feedback to help improve your site!
I'd also suggest creating a Contact Us page as shown here so your customers know how to reach out to you with any query. Best practises, examples and why a Contact Us page is important for your store is discussed at length in this blog post if you would like to take a look. Also if you have created any social media pages for your business, this too can help increase sales and gives your store a more professional and branded look as mentioned in this guide. I'd suggest adding these to your store for sure! You be able to add them to your theme by selecting Online Store > Themes > Customize > Sections/Footer > Social Media or depending on your theme, you can add them by selecting Online Store > Themes > Customize > Theme Settings > Social Media.
How are you finding Shopify so far? If there is anything else I can help you with, please let me know, I'm happy to help!