I have a 16 week old staff and don't know what she is crossed with. People keep saying a boxer and others say a pitt. Please help.

Boxer was first the thing that came to my mind.

Same here, boxer. Wait a little longer maybe as she ages more traits will appear

Staff as in American Staffordshire Terrier? She has socks like a boxer I can tell that, but I don't know many dogs that come out brindle, unless they are part of the mastiff or terrier family.

I rescued a brindle/white boxer last year. She had more white than brindle though.

Yep, Boxers are part of the mastiff family.