First big argument me and my girlfriend have had, what should I do?

[Joe]

Basically, this morning I saw my girlfriend, but we were playing a game with a load of friends and I jokingly said that she was rubbish. Then after the game as we were talking she refused to hold my hand and ignored me for about 30 mins, and then when she saw that I was upset about it held my hand but still didn't talk to me (we were kind of in an informal lesson at the time). I kept on saying I love you, and things like that but it didn't do much. She's having a really tough time at the moment and I feel really bad for what I've done. So anyway, after the lesson she did talk to me, and we hugged and I said I love you and she did say it back. We did also kiss very briefly, literally just a peck on the lips as opposed to what we would normally do. But anyway, I asked what was wrong and she said that she's just tired, but then she said you called me rubbish, and I could tell she was really upset. So I apologised straight away and she said I forgive you, but I could tell she was still upset. I was thinking I might go to her house this evening with a card and flowers to make up with her, would that work? Thanks for the help.