Don't worry, mistakes happen. In your case, mistakenly selecting "yes" for being the only girl child in your JEE Mains 2025 application, when you actually have a brother, might not be a significant issue.

The JEE Mains application doesn't explicitly state that incorrect information will lead to rejection. However, it's essential to ensure the accuracy of the information provided.

Since you've already submitted your application, and the correction window is closed, you can't make any changes now. But, as you mentioned, you provided the correct information in your NEET application, which is a positive sign.

To be on the safe side, you may want to:

- Contact the JEE Mains authorities: Reach out to the National Testing Agency (NTA) or the JEE Mains helpdesk to report the mistake and seek their guidance.

- Keep your NEET application as a reference: Since you provided accurate information in your NEET application, you can use it as a reference point to demonstrate the correct information.

Remember, honesty is always the best policy. Being transparent about the mistake and taking proactive steps to rectify it will likely work in your favor.