Ladies like yourself always deserve to be called Ma'am anyway. I know some women take it the wrong way - like we're 'ma'am'ing them because they're older or something. But where I come from it's a sign of respect. The only woman I don't call Ma'am is my sister, because I think she'd probably hit me for it.
You're joining their team? That's good. I think that team needs more girls on it.