Age for using connecta accessory strap

[Summertime10]

Hi all, I'm excitedly waiting for my connecta arriving with the postman today. My question is- will I need to use the accessory strap to narrow the width? My son is coming up to 17 weeks old and about 13/14 lbs ( tracking just above the 9th centile).
Thanks!

[Gotakeahike]

Depends on how long their legs are really. It should go knee to knee without bunching. If it bunches, sinch it in with the strap. IIRC, I needed to use the strap at that age.