General advice is around 8 months I believe x
Different prams say different things, look on their website or in the manual. It’s usually 6m due to their spine development
I believe they are ment to lie flat until 6 months. My daughter was also ready before then and used to push herself up to see over at 5 months, which was really cute lol. We stuck to it though.
My oldest was about 4 months but she outgrew the carry cot bit and so she went into the pram bit but parent facing and as flat as possible I didn't turn her or sit her up more until around 6 months when she was almost sitting independently x