I'm sorry this happened
It's considered rape since you told him you wanted to wait until marriage and you asked him if he wanted to stop since you didn't want to have sex, yet he still "shoved it in." Even though you consented afterwards, it's still considered rape since you said "no" to begin with. And seeing as he outright admitted it, that's not even a doubt in my head that he knew what he was doing.
This is not your fault..
Have you reported him? You definitely should so this doesn't happen to any other girls.
Stay strong.
PM me if you'd ever like to talk, about anything.
<3