my site has about 7 plugins and all work perfectly and do important things visually. Is it a concern that sometime in the future some plugins will be updated and will no longer work on my site? Maybe wordpress will update and cause these plugins not to work. I don't know much programming. If these are possible concerns what should I do and how can I prevent my site from going down?
Realistically this shouldn't be too much of a concern. The plugins that are available, usually, are supported by a community of users who find, troubleshoot and fix issues and errors in the plugins. It IS important to update your plugins for the reasons mentioned above.
At the end of the day though, it's just javacript and PHP... Worst case is that you'd need to hire a developer to fix the problem that arose, any true developer with a few years experience can repair most anything.
If all else fails, post a question here, I'm sure someone would be able to help you.