It really varies from child to child. I have 4, my last two (twin boys) stopped using the high chair at 18 months. I knew they were ready to eat like "big" boys, because they would kick their trays off when they were done eating. Try her at the table with a booster and see how she does. If she is unable to maneuver eating with "minimal" mess, she's probably ready. If not, gradually acclimate her until she is. Hope this helps!