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 ?
It should be normal practice as long as you have a reason to delete it.
I think many people have deleted their own posts for some reason - but if the posts are deleted in large numbers then perhaps some monitors will question the purpose of your actions. I know that's not why you deserve the tag - but something like that is always suspicious.