Hi Jacki (?)
It would save a huge amount of time and $$ if you use a pre-existing platform. Have you looked at using existing private social media platform like Mastodon?
There are a other few highly-regarded community platforms that you could build it on.
e.g. Vanilla Forum, Lithium, Jive, Discourse, Higher Logic
Some of them are pretty amazing – just about every feature available out of the box.
e.g. Spotify uses Lithium for their user community. https://community.spotify.com/