If you're comfortable with that decision, go for it. Just remember one thing: if you're quitting weed just for her, you might regret in the future, maybe even resent her for making you quit. If you really don't mind quitting go for it, but if there's a doubt, talk to hre about it, if she likes you you'll work out a compromise.

Something I learned when dealing with girls: don't change for them unconditionally, unless they change something for you too. Otherwise, it isn't fair and you'll resent her for it eventually.