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If your Mac is low on startup space, I WOULD STRONGLY RECOMMEND to free space by deleting unwanted applications, movies, musics etc and empty the trash. If you don't do this, then your Mac will crash soon. I've seen this happened before. Macs need at least 10GB of free space to work properly.
You don't need to delete Element 12. Go ahead and install 14 and it will upgrade. If you have purchased it as an upgrade, then you need the version 12 to be there to install version 14. Elements don't take much space though even if the version 12 is there.
You can use this application OmniDiskSweeper to find what files are using up all the space and delete them if they are not needed --> https://www.omnigroup.com/more
(Do not delete your iPhoto Library or iTunes Library or any important files)
Make sure to empty trash to free space. If you have any questions or would like any additional information, please don't hesitate to ask.