Of course you can!
I am in the middle of a migration project, and the team I am helping with has several Git repositories (converted from other version control systems) to upload to their Team Project.
It isn’t extremely intuitive – you need to open the Control Panel for your Team Project (https://yourserver.domain.tld/yourcollection/yourteamproject/_admin/_versioncontrol)
and from there you can create a new repository.
When you’ll navigate to the newly created Git repository you will get the Getting Started page as well, which is very helpful for first-time users.