I have lost 2 babies at a similar gestation OP, and I’m sorry for your loss - reading between the lines there may be an extra element to your grief but you needn’t feel that way. Babies don’t make it for many reasons and some need hard decisions to be made but they are deeply felt losses nonetheless, or more so.
I miss my babies every so often, I think about them, but I’m not sure I can remember the dates they were lost. As you know, they don’t get birth certificates, death certificates, funerals or memorials or any form of official or legal recognition (this is changing now). We don’t get the time with them that we might have if they were a little bigger, we don’t get the little mementoes like photos or footprints or locks of hair that we might have if they were stillborn. We just get a traumatic experience and a sudden ending. It makes their dates more fuzzy and less definitive in my experience. No one in my family or friends of any type speak about or acknowledge my lost babies, the vast majority do not remember that they ever existed. There were cards and a head tilt or two at the times I lost them, but the road to parenthood is extremely bumpy, a majority will experience loss, and they do often become a bittersweet side note of life. Important to us, yes, but to others, most likely not, and that’s really to be expected.
Its OK to talk about them though, any day of the year - I wouldn’t expect anyone else to remember but I would expect them to be kind when you are down.