I'm 20, and underweight so I assume age + weights will help significantly, but the question here is,

When I'm with friends for example I get overly excited that my voice is feminine, squeaky, higher pitch, friendly, etc. Sometimes I would watch videos people recorded of me and I would actually sound like I was gay man.

If I try my voice can be deep, but in these kinda situations its "natural" for me to sound like above ^

How can I develop a more stoic, confident, masculine voice?