If it's that one time or even several times over a long period of time, then it's normal and there is nothing you need to do or worry about as your system is reported clean(no filesystem errors detected) ... Sometimes errors would be found and automatically fixed and that would also be normal and nothing needed to be done from your side.
This is probably the first time you notice it, but it most likely has happened before and might("will happen") happen later ... You might find some already had happened if you look into the logs with like for example:
sudo grep -2 'recovering journal' /var/log/boot*
Shutting down Ubuntu gracefully does not guarantee a clean filesystem as other things could happen ... Also a filesystem check triggered at boot doesn't necessarily mean a big catastrophe has happened ... In fact most of the time, the filesystem will report as clean like in your case and other times the problem is minor and limited to a single or few inodes like for example a deleted file/directory that its inode was not properly freed due to it was being held open by a process when it was deleted.
Please, see this post which might shed some light on what might trigger a filesystem check as well as what might need user intervention regarding that.
