Most experts suggest waiting until your little one reaches the 9 to 12-month...

https://www.first-bookmarkings.win/most-experts-suggest-waiting-until-your-baby-turns-one-they-need-strong-neck

Most experts suggest waiting until your little one reaches the 9 to 12-month mark. Your baby needs strong neck muscles to support the weight of a helmet comfortably. They should sit upright easily without any support