Yes. Of course you can change your mind about making an adoption plan. Making an adoption plan for your baby is a voluntary decision and you should only do it if you feel adoption is in your best interest and/or the best interest of your child.
Until the termination of parental rights hearing you are your child’s legal parent and you are the person who decides what is best for your child. The termination of parental rights hearing is a court hearing where you are asked by a judge if you consent to voluntarily terminate your parental rights to allow your child to be adopted by the parents of your choice.
If you change your mind and want to parent before your parental rights are terminated by the court you can make the decision to parent regardless how far you are engaged in the adoption process. The important thing to remember is that you are the decision maker when it comes to your child until you consent to have your parental rights voluntarily terminated by the courts.