My cervix seemed to be my LO's favorite thing to kick from 18 weeks till about21 weeks. Now she does it every once and a while and Im now 25 weeks. I highly doubt its anything to worry about because if it was Im pretty sure if it was practically everyone would have to worry since everyone I talk to said their kids did the same thing.
I'm 27 weeks and she's always kicking or punching my cervix. She will go from feet down to head down, she mostly stays head down and punches it though. Hasn't hurt me or anything during pregnancy so far, just makes it uncomfortable when she does it.