NTFS Auto Mount

I read an article about Self Hosting and got interested to try Syncthing. I set up a Raspberry PI and attached an external drive. The drive is formatted using NTFS. I noticed ntfs-3g is already part of the OS on the Raspberry. It seems the Raspberry is mounting the external drive under /media/pi using the fstype of NTFS. I have 400GB of free drive space, but Syncthing says there is no available space. Is it really telling me the external drive is read-only and I need to change the fstype to ntfs-3g?

It might not have free disk space for the database, which is stored in the home directory.