I think you are right not to force her to be handled by people she is worried about. Letting her wander on her own and investigate people if she feels comfortable is perfect.
It's funny, because Panda is not the least bit shy of most people. But we were practicing the "stand for exam" once for obedience, and I asked the secretary at one of the training centers I go to to "examine" her. (which for Novice Obedience means a single touch on the head, shoulders and rump) I didn't realize until she came out from behind the counter that she had a big fluffy poncho-type sweater on, and clinking bangle bracelets. Panda freaked! She wouldn't let her anywhere near her!
I;ve practiced the stand for exam many times since them with other people, and she's fine, but I want her to get over her fear of Leigh. So every week, when we go to that training center for agility, I give Leigh a handful of cookies. I stand in the office door, holding Panda's leash. She doesn't have to go in, and I don't encourage her pr
say anything. When she gets up her courage to peek in, Leigh tosses her a cookie. When she has taken several, Leigh can usually toss them closer to her feet, and Panda will go get them. IF she gets the cookie and stay looking for more, I have Leigh hand her one directly. If Panda takes the cookie off the floor and retreats, we don't push her any farther. Since Panda is, in most circumstances, a very confident puppy, I'm sure she'll get over this. But I'll take all the time we need to do it. If she were a shy puppy, I'd STILL take all the time she needed, but I'd be doing the same sort of thing with lots of people, not just one.