Most Helpful Girl
For the most part, it's extremely, extremely sweet. I notice the little things about a guy, so it's nice when some actually appreciates you enough to notice the small things, and remember the small facts. It shows you were more interested in her than in yourself.
I've only had one bad experience with this: if you rattle off my history in the hopes of trying to impress me (versus being coy/subtle about it), it's a bit strange. I had a guy who I barely knew ask me to be his girlfriend. I then told him we needed to get to know each other better, and he said, "what are you talking about?! I know you!" and began recounting a laundry-list of my favorites/family history/all that stuff (your favorite color is green, you have two brothers, you hate football, your dog's name is...you get it). Things like that don't show that a guy knows who you are as a person. So as long as you don't brag to her and claim to know her based upon these things, you're golden.