yeah don't give her the roses...or do anything out of the usual right now. what sucks about girls bringing things to your attention is you can't really do anything to change it immediately or otherwise you do look like an ass who's trying to suck up/make things right. it kinda comes off as corny and next thing you know she'll complain to you about EVERYTHING all the time in hopes that you'll jump at the snap of her fingers. know what i mean? For the record...(coming from a guy) she doesn't want the damn roses. she just wants to be considered and be made to feel important to you. girlfriends want to feel more important to you than your own mother. thats the truth. they want to be number 1 in your life and you gotta make her feel like she is. I hate gf's family functions. they always suck, i feel uncomfortable, its a miserable time for me. i still gotta do em and so should you because by you going to the family function it shows her that you care about her feelings and gives her the illusion that you like her family...which is important to women because if they are serious with you they want you to like their family in the hopes that things will be good if you two end up together (like baby, married, etc) so all you REALLY need to do is consider her. make her feel important...ie. just dont be selfish. its really simple. as far as gifts go my advice is: give/do nice things for her randomly. never just give her nice things or do nice things for her on special dates (ie. her birthday, your anniversary, etc). for example...sometimes ill drive down the street and come across a makeshift flower stand (they pop up from time to time where i live) so i'll stop...get some roses/flowers and take them to her, etc. just because. no special event...not a peace offering after a bad fight, etc. just because. they fucking LOVE that. seriously. it shows them you were thinking about them for no special reason.
This is a dumb idea, and pretty much laughable. OP, your nice gesture is a good idea, but never prompt something like "This is the new me", "I'm gonna change" BS unless you really take the time to make the change. The change shouldn't come in the form of a gesture, the change should come from you genuinely. Instead of being selfish, change your behavior, change your ways of thinking first. Let her notice the change herself, show her instead of telling her. That will mean more than flowers, or any other gifts you could give her. If you say you're going to not do this or that, and you revert back into your old ways, it's just another disappointment she can add to the list you know? Then if you honestly can't make the changes, then that's just you and she can either choose to deal with it, or walk.
OP : I say give her the roses... and may be a gift as well. In a box. And may be a short note... a line or two... or if you like, a poem...