Breaking Into 18yo Asshole

I thought it would hurt her a little, actually I was hoping it would be very painful and that she would scream, that would make me horny as fuck, but no, my big cock break into her 18yo asshole like a bird but she was still very tight. I was trying to fuck her as hard as it was possible to make her scream and beg me to stop, but she just continued smiling and that made me a little angry, what the fuck is wrong with today’s teenagers? When they get so experienced in anal sex?