Willow, first of all, your friend is only his/her impression...I'm not sure there's a way to quantify your emotional "age".
I don't see any reason to cancel your date in the 13th. Even if you have issues that need to be worked out, you also need to get into the social scene. This is only a date, a chance to socialize with a man. And you need that to move forward, too.
A date is just fine...you may want to be careful not to move too fast, until you feel more secure of yourself, but I definitely think that going out with someone would be good for you. Staying alone seems to be to be a way to stay stuck in the same place. Anyway, that's my two cents.
Whatever you decide, take care of yourself. And don't worry about writing here. We all need some time away now and then. But you know that whenever you need some help and support, we're here for you.
*hugs*
mj