Baby less hair growth. Get full hair.

Hi my baby is premature born at 32 weeks on May 18th..she was born with very less hair especially on top so on 9th mnth completing we made her 1st shave on Feb 13th ..now 1mnth( 10th month completing) over but I see very less hair growth again especially on top of head..is this normal when will my baby get full hair..according to genetics mine is very long and strong hair..even my husband has good hair ..plz help me iam worried as again in may her 1st birthday..i am regularly oiling her hair..washing her hair for every2days..combing using castor oil ..even applying vitamin e capsules ..but I dnt see proper growth other than hair she has no problem with growth weight and everything is fine.. please suggest me wat to do..attaching pics for reference