Making your system accessible via the internet is not to be taken lightly. There are bots out there probing systems to find vulnerabilities, and if they find anything then you will be hacked. Also it is not only the device open to the internet that is at risk. Once a hacker is into your network then your other systems are at risk too. Unless you are prepared to put in the effort to keep the system safe then don't do it. If you just need simple notifications and control then possible using something like Telegram may well be enough.
See this FAQ post for advice on how to safely access node-red over the internet.
