Should I Be Concerned About Having No Post-coital Bleeding?

i am 20 year old girl.at the age of 19 i did my first sex.now almost 7 times i did sex but i didn't get bleeding any single time.i didn't use tampons, riding horses and also i didn't do any sports activities.my question is this why i am not getting bleeding after or during sex..plz help me..thx in advance