Your puppy is only young and needs to understand what is good behaviour and what is bad behaviour. Teach her that growling is bad behaviour - don't let her get away with it. Each time she growls at you, say "NO!" in a very firm voice. If your voice doesn't stop her, gently but quickly tap her on the nose or gently poke her in the neck. (It's similar to the mother giving her pups a small nudge or swipe to let them know they've done wrong.)
If you don't want to be 'physical' with her you could simply scowl at her and point a finger whilst telling her "NO!"
If she growls when you or other people hold her, don't put her down until at least 10 - 15 seconds after she's stopped growling. If you put her down each time she growls she'll learn that her (bad) behaviour works for her, ie if she growls, she gets put down - just what she wanted! If she just growls at others, get them to give her a doggy chocolate drop or small treat - teach her that when other people pick her up, something good happens to her.
I strongly recommend you also give her plenty of training. Join a puppy training class as soon as you can as this will help to socialise her with other puppies and their owners. Additionally, the trainer will be able to observe your puppy's behaviour and may be able to recommend a course of action.
If you want to practice some puppy obedience training before you enrol in classes, you can do so by following the link. You'll also find links to pages with more puppy training tips at the bottom of that page.
You are right to address this now as your puppy will not 'grow out of it', she will simply learn that she can get her own way by growling at people. If it continues, sooner or later, it will lead to further aggressive behaviour.
I'd like to point out that I'm not a behavioural therapist and that if her behaviour gets worse, or there's no sign of progress, please get professional help.
