My biggest worry for you OP is that it doesn’t sound as though you have anybody who can support you both physically and mentally, particularly in the early days/weeks/months, especially coupled with history of depression which increases your risk of developing postpartum depression. But even once you get through the newborn trenches as PP says it’s lifelong, nursery, doctors appointments, pick ups & drop offs, always something to buy, and if you don’t have the support of family or a partner you won’t have the chance to go to the gym, to get your hair done, to go for a coffee or few drinks etc and I can imagine that would be really difficult.
There’s also the things that (especially if you have a difficult birth) you need support with postpartum like help showering, cooking, if you have a c section then even help with shopping, feeding & lifting baby, I had to take medication after birth for awhile and that made me feel really unwell, sick/faint, it was manageable because I had my husband to look after me & baby but I don’t know how I’d have coped with that if I’d been totally on my own. Is there a friend or family member you are close to who could take the time to come stay with you for a little while, or a way you could rota to come everyday? One of my best friends became single while pregnant so was a single mum when she had her baby, she spoke to us all about her worries beforehand and we got a rota set up so we took it in turns to stay over, go for the day, cook meals etc, so she was never truly on her own, is that kind of thing possible for you, if you spread it across a few friends?
I am quite a practical person, so if I was you I’d try to suss out what support I have, what support I could afford to pay for if I don’t have it in friends/family, and then see how that looks.
There are lots of single mums and they are superheros in my eyes, but just based on my own experience it’s not something I would choose for myself.