Woah, you are 100% not in the wrong; he is.
HE groomed you, he was aware he's literally criminally older than you in this scenario and He had the legal responsibility to recognize that and break off the connection AS SOON as he knew you were a minor. Then there's the blatantly lying by presenting himself as a minor/teenager.
He's lucky to not be in prison right now. That's exactly where this would and should have led if it had continued.
and also said that I groomed him and tricked him into going out with me.
This statement is an attempt to scare you away from reporting this to authorities, so he doesn't face consequences for his blatantly illegal actions.
Please don't feel bad; you did nothing wrong. I wish you the best of luck in the future. :)