If you're still looking for a useful response, then the answer is: it depends on your mood. If you haven't been laid in a while, and you're horny as hell, then getting off prior to seeing a girl isn't such a bad idea. Tylenol or Advil apparently works as well, though I've never tried it myself. Also, since this is your first time seeing an escort, if you are feeling nervous or apprehensive, you may find it difficult to get off or even keep your pecker up, as I did the first few times when I started. I remember the second girl I saw was hot as hell, but couldn't get off because I was so nervous.
Personally, pre-jacking off has never worked for me, and in fact gives me the opposite of the desired effect, since what you're really doing is numbing the feeling on your penis, and making yourself more relaxed (aka: tired). I find that in most cases, the rubber numbs the experience enough to let me last a desirable length of time.