Here is the deal:
A woman will only date a confident man. So if she is on a first date with you she assumes you are confident. If she determines that you are not confident, this will be two dates in one -- first and last.
You are a man. You go after what you want, because you want it. If you want to hug a girl you hug her. You don't wonder whether or not she wants you to hug her -- the point is that that is what YOU want, and moreover, your wondering if it's okay is an excuse, a stall tactic to use on yourself because you are NOT confident. Forget wondering, just be confident.
Now, the reason there is nothing wrong with hugging is that it isn't invasive. You don't kiss a girl at the beginning of a first date because it is invasive -- you are involving an orifice (her mouth), and even a kiss on the cheek still involves YOUR orifice. Orifi = invasion, so she first needs to feel comfortable, safe, even aroused, with you.
By hugging a girl you show her that you are confident. She knows you wanted to hug her, otherwise you wouldn't have done so, and since it involves touching she knows you are not nervous or afraid. She wants you to be confident and to SHOW her you are confident. Also, girls like to hug, they like to touch. By hugging you show her you are affectionate, and girls like that. Also, it does set the tone for more intimate touching later, since you start a date with touching/affection, then have a great time and make her laugh and enjoy your company, she will likely be receptive to more touching.
Also keep in mind: if she assumes you are the way a man should be, 1) confident and 2) you go after what you want, then by not hugging her she may unconsciously feel that you simply are not very attracted to her.
Go for what you want. You'll find out if it's what she wants when you do so, but she won't let you know that until you go for it.
DJBe