https://support.mozilla.org/en-US/kb/firefox-crashes-troubleshoot-prevent-and-get-help

Sorry, but I have the lates OS and Firefox automatically updates. There's nothing wrong with my RAM or hardware. This has been going on for over a month. Now what?

Uninstall software known to cause crashes

Check your computer and remove any malware or software that might be causing problems: Check the release notes to see if there are any known issues for your version of Firefox. ... For more information, see Troubleshoot Firefox issues caused by malware.

https://support.mozilla.org/en-US/kb/firefox-keeps-crashing-startup