When should I worry? 13mo talking

My son is just about 13 months old and he’s only saying mama and dada, though only on occasion. I’m a ftm and am unsure of what’s worrisome and what’s not since he is still so young. Sometimes when saying mama and dada, he doesn’t seem to be using it to address either of us either. He just sort of says it. He also calls me dada occasionally. His pediatrician didn’t seem worried at his 12m appointment, I’m just scared of something being wrong and probably am thinking too much about it and comparing too much to other little ones. He doesn’t mimic words, but will mimic some basic sounds sometimes. He also doesn’t have any other words he says but he understands what milk and juice mean. Would you be concerned too?