Hi Darcy and welcome,
Yep, it's quite natural for your dog to pick up your fear or caution towards others. Why should she be happy and fearless if you aren't? So you need to work on your timidity in conjunction with her uncertainty.
When she growls at someone when you meet them, tell her "NO". Don't accept it. If she continues, walk her in a circle right back to the person. It's a break and a reset, imo.
Her wag is possibly showing that she's conflicted on how to behave and she's trying to get a read from you about what to do. Have her sit to meet someone and make it a semi-formal occasion where you are in control. Obviously, 5 minutes after she's figured out it's ok for the men to be around. You want her to see immediately it's ok and not 5 minutes later.
Personally, I prefer people to scratch my dog under her chin. Otherwise her eyes are blocked for sight, and it also makes her actually look at them instead of just some large hand. But that's me. It's made my dog a lot more confident of other people....she's also a small dog, so a hand suddenly emerging to pet her on the head is quite startling.
I hope this helps give you some ideas ....but you also have to work on your fear. I can understand it completely. I've had problems with gangs of males in the past. Even if she lets out a small growl when she sees a grouping... You could tell her to "stop" and "ok". You know she's worried, but you're the one in control.
regards,
toodles