YOu should get the other parent to sign off, It would be wise to do a suit affecting the parent child relationship so that you can have an order to set out the rules of the relationship
You live in Harris County so go see a family law attorney. Look on this website & select one.
You can look on my website for 2 that I recommend - www.familylaw4u.com - they are reasonable.
You need to get legal custody or you probably won't be able to take the child to a doctor and/or register the child in school. Also, your cousin will be able to come and pick up the child if she gets mad at you. I would want "legal custody" if I took a child into my home to raise & love.
Thank you for doing this for this baby. Do it legally and the right way - you will be glad that you did. I've received phone calls from people that don't -- then it's too late after you've grown to love and care for the child!
Fran Brochstein has over 20 years legal experience & enjoys educating the public about Texas laws. She is a full-time family law mediator in the Houston area. If you found this answer "helpful" or "best answer", please select the button to show your appreciation. Please understand that this is not a personal consultation and in no way creates an attorney-client relationship. You are strongly encouraged to consult with an attorney in your county in person about your specific legal problem. You can contact her at 713-805-9591 - 7 days a week - her personal cell phone.