Hey OP,
I know it's not exactly the same but I fell pregnant accidentally when I was 34 and I split up with my BF when I was 6 weeks pregnant. He has never seen the babies, and I've never taken a penny from him in financial support. After we split up, he just stopped replying so I decided to go it completely alone from about 8 weeks pregnancy onwards.
As it turns out, I was pregnant with twins. And as it much later turned out, they're both autistic (one particularly has high needs). They're now 13 years old and it was singularly the best decision I have ever made.
Yes, it's been tough at times but being solely responsible for their wellbeing and being able to bring my children up in the manner that I want without having to compromise on parenting has been wonderful. We have a calm, relaxed household and my DC are just bloody lovely (although I may be a weeny bit biased).
I do actually have a DP - someone who had been a friend for years before the DC were born. My DC call him daddy, but they're well aware that there's a biological donor out there who made them. (In fairness, DS doesn't really understand but DD does).
You need to be well-organised and prepared, and to consider what will happen on the days when things don't go to plan - eg/you get a call because one of them is sick at nursery, school etc. What will happen if your shift runs late? And so on. I actually switched from a high-stress, long-hours job to self-employment. (They were born prematurely and had medical needs for a while, hence the switch).
It is difficult at times - god, I remember those sleepless nights trying to juggle two babies on my own!!! But the good times FAR outweighed the difficult times and I would do it again on my own, without question.