Slow your roll dude

So in my last entry, I informed all you viewers out there that, by some miraculous blessing from above, I received a response back about my resume and cover letter email I had sent to a local real estate company looking for a property manager's assistant.  After what was apparently a successful phone interview in which I said everything the realtor needed to hear, she asked if I could come in today for a trial shift and work 8:30 am to 5:30 pm and see how I fit in the position.  Without a second thought or hesitation I immediately said yes.  As I processed this last night, and then this morning after waking up, however, I realized that I definitely made quite the folly.
It's not that I don't want the position.  I actually really do want it and think that I'd be a perfect fit for what they're looking for.  The problem is, I'm just not prepared to show up for a first day at a new job and be fully prepared, equipped, and dressed appropriately and ready to knock their fucking socks off;  it is just too soon to just jump right in and expect to make a good first impression.  For starters (as an example), I don't even have any slacks/dress pants that are work appropriate.  All I have are jeans, and she said the office dress code attire is business casual, and I am not about to walk into my first day at a new job wearing jeans thinking that I'll be taken seriously and look professional for my first impression (and first impressions are EVERYTHING).  I don't even have a black/leather belt to wear with said pants, and I don't have a work acceptable day-bag/messenger bag, all I have are backpacks because I'm usually out in sandals in shorts on the bus with my back pack lookin' like a college student every day.  So basically:  I'm not ready to show up at a new job fully prepared and know that I'm going to exceed expectations.  And if I'm not fully prepared and don't have my bases covered and am not ready to wow them immediately upon meeting me and seeing what I'm capable of and what I can bring to their office, then I won't go until I AM ready, because I want to show them that I would be taking this job seriously, and that I am there to wow them, not disappoint them by showing up under-dressed, ill-equipped, under-prepared, and just sloppy.  So hopefully I can push it back one more day and use today as my "prep" day to get all my affairs in order and hopefully the boss lady (Coco is her name) is willing to reschedule for tomorrow.  I really REALLY want this position.  I hope it's in the cards for me.