If I agreed to terms of a website, but now don't want them to have my information can I delete it somehow?

Go into your computer and delete any cookies from that web site.
If you had to make an account for that site do what you can to de-activate it.
If you get email from the site spam ,it block it, junk mail it.
That is all I know hope all or any of it works for you.

Theoretically, yes. There is supposed to be a way for you to tell them to forget you.

Actually, no. They make it so difficult that it is well night impossible – and even if one website has deleted you, they probably sold your data three dozen times and you’ll never track every other partner down to get your stuff deleted.

So… for all intents and purposes, the answer is NO.