Your feelings and approach towards your daughter are completely valid and understandable. Many people feel that the term "stepchild" can carry negative connotations or create a sense of distance between the parent and the child. It's essential to focus on the love and bond you share rather than labels.
Choosing to refer to her simply as your "daughter" reflects the emotional connection and commitment you have to her, regardless of any legal or biological distinctions. By doing so, you are emphasizing the importance of your relationship and making her feel accepted and loved as an integral part of your family.
Ultimately, the way you choose to address your daughter should be based on open communication and understanding with her. It may be worth having a conversation to understand how she feels about it and to ensure she feels comfortable and respected by your decision.
Different families have their unique dynamics, and what matters most is fostering a loving and supportive environment for your daughter. As long as your actions and words show love, care, and commitment to her well-being, you're doing what matters most as a parent.