Agree, but it would be wrong to call it agression. Imaginary catch of that squirrel. Sometimes dogs bite people during dog fights, sometimes they bite during dog plays, they bite their handler's encouraging hand instead of the sleeve, they bite your hand if you try to cheat them with the ball. They bite whatever is there instead of the object they intended to bite, because biting is in their head and they cannot wait to start playing. That is one thing, do not mix it with snapping at your face.
That fact that she's snapping at your face tells about her attitude towards you. It is normal for dogs who are friends, and used to play rough games - to touch each other neck or face with their teeth. In the doggy language it may mean reestablishing old relationship, greeting, inviting each other to play, or simply drawing attention. So, probably, she speaks to you as she would have to another dog. But, human face and neck has different texure than the doggy's furry face and neck. Try to avoid accidents, but not the way you do it. You hide from her with the lead, she snaps, and that has become a part of the game.
You have to give her some alternative what to do instead of snapping. Does she like to bark? Ask her to sit, hold the lead behind your back and ask her to bark. She should bark not less than 10 times, reward with a treat, a click and immediate play. Very often introducing something new like a clicker helps to change the behaviour. You know the moments when she's most likely will repeat this behaviour, and, if she does, you know the sequence of your actions, train her new behaviour. That, which pays back (food and desirable click) would remain, and that which doesn't have any outcome would gradually go away. The risk here is one - she might start barking more often and for longer, and not in times when you want her to.