Help with percentile of a premature baby..

[Bala123]

My baby was born at 36 weeks because of preclampsia, his birth weight was 3 pound 14 ounce ( 1.7 )kg. Today he is exactly 4 months old that is 17 weeks but if i’ll Do his correct age he is 13 weeks.can anybody help me with telling on which percentile he is right now. Today I checked his weight he is 5.70 kg
I have attached his percentile chart in his red book.. plz help me with that.. thanks in advance

 

[Chase]

I know this was posted a while ago and you probably have an answer but thought I'd reply anyway. You should correct his date by 4 weeks to plot it up until he is a year old then you stop correcting