Well, I am not sure my intent came through with my question. I will assume you are in America, and we are talking American sizes and that you are average height, 5’5”, so of course any of these assumptions could be wrong. If you are size 6 or smaller right now, I think losing a little weight won’t matter to the guy and how he perceives you in terms of thin or not, you are thin. I understand you will feel better psychologically to diet a little, but I am trying to go from an objective standpoint of how people will perceive your weight. If you are between an 8 and 12, losing 5 or 6 pounds could make a significant difference in my opinion. If you are 14 or over, I think the 5 or 6 pounds wont make a significant difference, similar to the size 6 and under. I am talking totally superficially, and subjectively of course. If you are much shorter or taller than 5’ 5” my numbers don’t work.
You can easily make a date for a week from this weekend, give yourself almost two weeks to lose a couple of pounds, but the date making will feel more like you are just pushing it off for one week, because it is a week from Friday for example, and middle of next week buy a new outfit that you feel slim in.