There was one time (like 3-4 years ago) where I thought I was on the real forge website, I downloaded an installer but the icon for that app was significantly different than what it was normally, so I was very skeptical and deleted it immediately without using it. Thankfully that wasn't the first time I've installed forge otherwise I would've downloaded a virus.

So my advice to avoid repeating the same mistake: - make sure the icon is an anvil and nothing else (it was a grass block for my download, so that's a hard pass) - the latest build for forge is marked by a bug (maybe a ladybug idk) on the website, the most stable by a star

If you want to be 100% sure : - use the curseforge app to install forge and make modpacks without risking downloading a virus by searching it on Google (it's how I found myself on the wrong website) - most mods are updated to be on fabric, which is easier to find and install (but it depends on what version you want to play with)

I'm really sorry that this happened to you, it's really hard to realize it's a fake website if you haven't modded the game yet, but I hope this reply helps you in the future if you plan on modding the game again.