Question mark in folder icon at top of Terminal

The window title reflects the working directory of the Shell.

• If your default is different from the (user) Home folder, i.e. changed to a custom directory, then the opening screen might point to a directory that no longer exists, or is otherwise unavailable.
• If you resumed a session, then working directory might point to a directory that no longer exists, or is otherwise unavailable.

Try

$exit

and quit the app, then launch again.