It is relevant to Norma McCorvey that she is against abortion, but it makes no difference in the discussion as to whether abortion is moral or immoral.
McCorvey was an important person in the abortion rights movement. It was her lawsuit that got the Roe decision handed down. But this does not make her opinion any more significant than anyone else’s opinion. She does not have any more understanding of the morality of abortion than anyone else (or, at the very most, than anyone else who has had an abortion).
Let us look at an analogy to help us understand this idea. We all agree today that slavery was a terrible evil. What if we could find someone who was a slave who then said that being a slave was not really such a bad thing? Would that mean that slavery was good? Most people would say that it would not mean that. All that it would mean is that one person who had been a slave thought slavery was a good thing. Their voice would not be more important than the voices of all the people who lived slavery and hated it.
The fact that Norma McCorvey now believes abortion is wrong does not mean that it is wrong just as the fact that she thought it was acceptable in 1973 did not mean that it was acceptable then. Hers is just one opinion.