That's a tough one. I will be completely honest with you. I never like to see anyone smoke when they have children. Even if they smoke outside, not around the child. It is on your clothes, in your hair, on your breath, etc. The child smells it. I would do all I could to stop smoking. (but, I'm not a smoker either, so that's easy for me to say) I smell it and I can't stand it, so I imagine the baby smells it also and they are snuggled up next to you. :cry: Sorry.
But....it is none of that woman's business to go about it the way she did. She could have said something to you in a much nicer way. IF, she thought you were too young and needed advice. Like, oh you might want to pick your beautiful sleepy baby up she's falling asleep in the cart.
My sister was 17 when she had her first child and by the time she was 21 she had 3 kids. Imagine all the "help" she got from little old ladies. It used to drive her nuts. (she was married, but nobody knew that)
Don't beat yourself up over it. You sound like you are doing a good job and thinking about the comfort of your daughter first! That is what is important.
I hope I don't come across too harsh. I never had children, but I was around my sister alot and she had 5 kids. They are all grown now and doing great.