If your are actively seeking dates with someone, the dating dream reflect your anxieties about dating. Dreams in this case are rehearsals that your mind creates for an actual date, like sometimes you would dream about a test before an dreams exam. It could also be about a past date that you have experienced.
What does it mean when you start dreaming about a guy?
Specially when you dream about someone, it is very likely that you were thinking about that person when you fell asleep. But going by theory, when you dream about someone, it has more to do with certain aspects like their personality, or the relationship you share with them, rather than the person itself.
Why did I dream of going on a date with someone?
To dream of about dating means that one needs to crush about how they project themselves in waking life. To date an old friend means that the dreamer has a crush for sexual affection, and acceptance. For those who are in relationship, this may dream the same but there may be some rejection.