Is 15 months old too old for highchair!?

Ok I posted a pic of my daughter in her highchair today because it was a cute picture. Someone commented on it that she is too big for a highchair!? I'm sorry, but did I miss some kind of memo here? She is 15 months old and 18.5#. My highchair in particular states it is good for use up to age 3 or 50#. I'm not saying I would keep her in it for that long but, what????? Am I the only person having my 15 month old still sit in a highchair? And why do people feel they need to "shame" other parents and act like they are experts on someone else's child? 😳🙄