Yep, my DS is the same age as your DD and he does the same thing. He loves to touch my other boob and god forbid I have no top on and he has full access to it, lol! He will pull pinch and flick at my nipple! Usually he just strokes and pats it. I love the way he appreciates his boo!
Don't let other people get to you leasha, it's their problem, not yours!