I like this kid who I am not aloud to text cause I don’t know him that well. However, last week I started talking to him again! How do I stop?

I am not entirely understanding the question. If the only issue in texting is not knowing them well enough, can you not get to know them more over text?
To answer though, just delete the number, unfollow the socials, and move forward. Maybe your paths will cross again in the future and the opportunity to properly get to know eachother will arise.