All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If this marriage takes place fulfilling the conditions of a correct marriage, then it is valid, and the woman’s statement that she will consider her marriage forbidden does not affect its validity. It is not permissible for a Muslim woman to forbid anything to her husband or anyone else (if she is not married) that Allah has permitted her to do. Whoever does that, whether married or unmarried and then marries someone she prohibited for herself must expiate by feeding ten poor people, clothing them, or freeing an enslaved person. If she cannot find to do any of them, she must fast for three days because that is like an oath.
Allah knows best.