3 month milestones

Lisa
My twins are three months tomorrow they were born 2 months early at 32 weeks my one daughter spent 4 weeks in the nicu and my other daughter is still there. My question is my daughter at home only smiles when she is going to sleep I've also noticed she doesn't follow items I put in front of her she kinda just wants to do her own thing. Is there a delay bc she is a preemie and should i be doing milestones at her adjusted age ? Any suggestions on apps or websites for milestones or things to work on