Hi! my LO has the same age as yours. She's also a preemie and as what I read they have delays or their milestones might take a while than those babies in full-term, but don't worry they will reach that certain stage too. But if you are really worried, you may consider to ask her Pedia for advise. ☺️
It’s okay if she’s not stable standing at 11.5 months corrected age! But good to practice some standing activities - you can try standing with back against the wall, standing at a table or sofa and playing with toys to encourage standing endurance and balance (1 hand free while standing)
Hi, my LO is 15+ full term but also not walking yet. PD said it runs in the family so don't be too worried unless 18m still cannot then let your PD know. Hope this helps!
I forgot to share, my LO can stand on her own but not that stable yet.