When does a step-(dad/mom) becomes a dad/mom? like over years or always introduced as step?

That's a question. I married my step-son's mother when he was about 14, so he was already cooked by the time I entered the picture. I have never felt like "Dad," and I rarely refer to him simply as my son.

In contrast, he recently became engaged to a woman who has two boys from previous relationships. The oldest is 5 now and his biological father isn't involved. My stepson regularly refers to this boy as his son, although the boy calls my stepson by his name.

different things feel right for different families. Dont feel bad if it doesnt happen immediately or never happens

I don't think there is a written rule for it, it comes naturally after a while I guess...and nothing wrong if it doesn't

nothing to do with time just personal preference from those involved and how they feel about the matter