Rules of thumb that I find useful is making sure that the solid food can be easily squished with my fingers. If not, it’s not safe for my baby. Gagging is normal and unavoidable, even if you serve puréed food. If the baby looks red, the baby is fine. If the baby turns blue, the baby is choked. I always practice the chocking first aid in my mind, just in case. Keep your eyes on your baby at all time. Don’t get distracted by phone and etc. It’s not only for chocking, older baby is capable of standing up in the high chair, hence the risk of falling.