Glad to hear that you're finding Shopify to be suitable for your business! Regarding the extension, that is certainly something our team can look into for you. Could you please get in touch through this link here and request an extension? The reason that I am redirecting you to this link is because we are not currently able to look into your account details via the Shopify Community.
You mentioned that the reason you would like an extension is because of a new project you're working on - could you tell me a little bit more? I would love to hear about it and see if I can offer you any more advice to help you out. Also, since you're still in the building stage, you should check out our Shopify Blog article on How to Start an Online Store - it is a really great step by step guide that you will find useful especially if this is your first time on Shopify.
Let me know if you have any other questions!
Lana | Social Care @ Shopify - Out of Office until Jan 2nd / Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog