DN is only 18 mo and I know all developmental stages are a benchmark and she could just be a little behind. However I'm not without experience in this (professionally) and I am genuinely a little bit worried.
From my observations she's not hitting any age related 'expectations' - no eye contact, mimicking, babbling, walking, cruising, words, pointing, responding to name etc.she's a gorgeous little thing and I love her to bits but for context I don't see her on a week to week basis and am not sure I have enough 'info' or the right to say anything. For context my dsis and I have a slightly fractious relationship and I don't want to overstep.
I have 2 older dc and would have wanted someone to tell me if they thought I needed to check anything out (DN is an only child so nothing to compare to) but I'm a control freak so recognise this isn't what everyone would want. I keep thinking perhaps she needs a hearing or sight test and it could be easily rectified.
Say something or button it?