Hello Olivia
You will probably have problems with the installation. Supported from Mojava 10.14, according to Microsoft website:
"Starting with the 2020 December Update (build 16.44) for Microsoft 365 for Mac or Office 2019 for Mac, macOS 10.14 Mojave or later is required to receive updates for Word, Excel, PowerPoint, Outlook, and OneNote. If you continue with an older version of macOS, your Office apps will continue to work, but you will no longer receive updates, including security updates."
https://support.microsoft.com/de-de...

Can you maybe update your MacBook to a newer version?