No Stupid Questions

This question doesn't really have an answer because the Internet, by itself, doesn't have an amount of data at all. The Internet is a computer network; it transmits data, doesn't store it. Computers connected to it do.

So you are going to need to define exactly what you mean, such as: all data accessible through the Web? Only data accessible to the public on the Web? Also data accessible through other services than the Web, such as emails on servers with no webmail interface?

Even then one problem with the question is that some data is stored more than once, for example this comment of mine will be federated to several fediverse instances, do you count it once per instance? Once per physical copy made during the operation of that instance (such as backups)? You can see that the question suffers from poor definition.

Youtube alone may be into the (low) zettabytes. I don't know if anything else comes close to that, but streaming services full of 4k movies is a lot of data, so maybe. Entire companies exist on AWS. Billions of individual devices are connected, so depending on your definition, all data that exists anywhere may technically be part of the internet (just not easily available).

Depends where you draw the line on what is the internet but it we would be well past the TB and PB likely into Exobyte territory when you consider data duplication.

that this with a hand full of salt https://thebestvpn.com/statistics/how-much-data-exists-in-the-world/

The data here is old now, but you might find this article interesting to give you an idea of the scale of the Internet. Maybe consider that Google tries to keep a copy of most of the public internet (compressed) and assume that the whole thing would be several times larger. Never mind that there is a lot that’s not covered by Google (paywalls, non-public forums/Facebook posts, etc.) but then also services like the Internet Archive that try to make multiple time-stamped copies of the Internet, although I think they usually don’t save the images/videos.

To be short, terabytes might sound like a lot to an individual, but the Internet is several orders of magnitude larger.

I remember seeing some estimates in terms of total amount of data (In terabytes) available via HTTP in the late 90s, but I think it'd be impossible to get a reliable estimate these days