The better question here is “How safe is my computer?”.
It has to be noted that a computer is only as safe as the weakest link in it’s defense. Is you computer locked inside a secure compartment with no network connection and a faraday cage surrounds everything like that scene in Enemy of the State? Is it sitting open and unlocked on a table in the public library while you grab that book you need that quote from?
You’ll also want to look at the more common sense things like software updates, anti-virus/anti-malware, and firewall as necessary. Having these all provide a degree of safety that should be a baseline in your defense.
Another key part of ensuring your computer is safe is training and awareness. That random popup telling you your computer is compromised and you need to spend $100 and install this software on your computer is more than likely a scam to get your money and have you install malware on your computer. That email from a Nigerian prince asking you to help him get his money out of the country is a very common scam. That email from Gmail or YouTube telling you your account has been compromised and that you have to login to reactivate your account, very possibly another scam.
You have to be aware of what you’re doing, what you’re downloading and installing, and where you’re entering your information. The internet is an increasingly nefarious place.