Realistically though, you had no money, no own home and obviously weren’t old enough to go it alone or you would have. What sort of life would the child have had? Your mum could see the bigger picture.
But come on, this is not a fair way to look at it.
It is exceptionally cruel and stupid to think that, in this situation, making the decision to 'go it alone' is a simple and obvious one. It's not.
Yes, perhaps the OP could have walked out. She's clearly torturing herself with the wish she had done that.
Or, perhaps, she wasn't remotely capable of that, and would never have managed to cope with a child aged 17.
But none of this changes the fact that, when she needed her mother, her mother failed her. Not because she couldn't support a pregnant daughter, and not because she thought abortion was the best option. But because she coerced her daughter.
Saying 'what sort of life would the child have had' is really unpleasant IMO - it's making the OP feel doubly bad, because you're implying (without knowing) that she would be a bad mother. We don't know that.
FWIW, I suspect aged 17 or 18 I would have been a rubbish mother. It's statistically quite likely I'd have struggled with it financially if not emotionally and mentally. But that doesn't mean I appreciated having the choice taken away from me, and at the end of the day none of us can know.
It seems to me that a big part of what the OP is mourning is not just the pregnancy she didn't carry to term, but the possibilities she'll never know about. Now that she is worrying that she may never have a biological child, it is natural she would be feeling especially sad that she never got to know whether or not she'd have been a good mother. Telling her unequivocally that she'd have been bad is just ... cruel.