Legal Question in Family Law in California

You can file in Texas, but you are probably more likely to get better treatment from a California court. If you are California residents and the child lives with you in California the courts of California are required by law to act in the best interest of the child. You naturally will have difficulty serving the natural parents in Texas but it probably be just as difficult were you to file in Texas. Further, unless you want to stay a long time in Texas while the courts act on your adoption petition you might just as well be in California. If as you say the natural mother agrees to the adoption then the whole process is better in California courts. The investigation of the appropriateness of the adoption will be based on the child's proposed adoptive family and her living situation in California. Good luck.