Anyhow I want to know that if we delete our posts ourselves, does it have a bad effect on our account and can we still get tagged or something or it is completely normal ?
Deleting some old posts likely won't get you tagged. But if you erase a ton of stuff you posted, people might wonder why and the internet never forgets. Things you put out there are hard to take back completely. Here on this forum, we have at least two archives keeping copies of posts even if you delete them from your profile. So once you hit publish, you cannot really hide it after that.