Hey Judi!
By default, Subscriber will not be able to post or edit events in the admin. They’ll be able to edit their own user profile and…that’s about it 🙂
Contributors, by default, will be able to post new events, but not update ones that exist in the admin already.
So perhaps adding “edit” capabilities to the “Contributor” role is your best option here – if so, then there are two ways to do this. One is with code, which is a pretty granular change to make, but you can also just use the famous “Members” plugin from Justin Tadlock to manually edit the “Contributor” role and allow them to edit events as well: https://wordpress.org/plugins/members/
Just some ideas here – let me know what you think and if there’s anything more I can help with!
George