Question: where are you two having this date? Is she coming to your place for tacos or are you two meeting at a restaurant? Hopefully it's the latter and not the former (though congrats if you managed to have her agree to a first date at your place).
Assuming you're meeting her at a restaurant, the first date is simply a chance to get to know more about her. Don't feel pressured to have to try and make a hook up out of it - if it happens, great! But that shouldn't be the focus. I usually end up hooking up by date 2 or 3 simply because I don't make having sex my main goal; I make it my goal to show genuine interest in their lives, and the women I take out can feel that genuineness, which ends up making them want me to do physical stuff with them.
Lastly, the date shouldn't be longer than 45 to 90 minutes - you want to leave her wanting to see you again, so it's best to get out while you have her laughing and thinking about your in a positive light. Anything longer than 90 minutes, and you risk saying the wrong thing or having her become bored with your company. There's less risk of this as you two go out more, but for the first date make it a point to end it. If she's all like "hey, why don't we go to this other place" after the meal, tell her you have something else to attend to - whatever excuse you have to make up, just GET OUT OF THERE. Tell her you had a nice time, give her a hug, and then go home.
Wait 4 days to call her, then hit her up again and ask her for another date. If the first date was successful and she felt something she'll say "yes" to another date; if not, she'll give some excuse that equals "no." But, assuming you're not texting/messaging/calling her in between the date and when you ask her out again, all should be well.
Hope this helps!
