Hi - my name is XXXXX XXXXX I'm a litigation
attorney. Thanks for your question. I'll be glad to assist.
The court is always required to do whatever is in the best interest of the child. Therefore, you would have the right to intervene/petition the court to name you as guardian instead of the other grandparent, or someone else. However, in order to do this, you would have to file a court petition and ask the judge to consider her being allowed to live with you.
The judge will look at the child's preference, home environment, family makeup, stability, financial ability to care for child, etc. The court certainly could find in your favor, but to throw your name into the conversation you will have to hire an attorney and appear in court. If you don't try to intervene, it's not going to be possible to gain custody.
Thanks for your question, and please let me know if you have any additional questions.