Is manager required to look old?

I have overall 15 yrs of experience in .Net domain. I have good technical,process and communication skills. Recently I attended a few interviews. I have been applying for an Engineering manager position for a couple of months. I cleared all the virtual rounds at multiple companies. The final round is just a formal meet and offer should be released by the HR. But every company is rejecting me at this stage. I am a 5ft, 50kg girl. I look much younger than my actual age.

Sometimes junior developers look older than me. After repeated rejections, I feel that they rejected me because of my appearance. Maybe they are feeling I am not older or mature enough for a manager position. The people who are taking the interview and being in a manager position look 45+ minimum. My friend told me those people don't allow people who look young to be part of management because they are jealous. they reached that position too late. She told me to apply for lesser roles.Is this really true? I don't know what she suggested is right or wrong. Am I overthinking? If yes, then what could be the reason for rejection? I tried to inquire but once they reject a candidate they just ghost them. I am not able to switch and it is bothering me a lot. Please help me with your suggestions