Is a girl's current unwillingness to marry the suitor (who proposed to her under pressure from her mother, and she does not feel the same love for him as she does for someone else), and her telling her mother that she will not marry now, considered a form of ingratitude for blessings, even though she feels comfortable with that decision?

The matter of choosing a husband is extremely important, and making a good choice is a source of happiness for a woman, while making a bad choice is a source of misery. Choosing requires deliberation, thought, consultation, and seeking guidance through Istikhara, prioritizing the qualities of religiosity and good character. Obedience to the mother is obligatory, and it is not permissible to marry without her consent. It is not permissible to engage in a relationship with a non-mahram man before marriage. As for loving a man, if it is limited to a feeling in the heart and does not extend to forbidden speech or actions, one will not be held accountable for it.