Some women don't bleed after sex. Usually the bleeding, if any, is because they or their partner is unexperienced or is a little too rough. The vagina and female organs are sensative and bleed easy.
Also, if the hymen isn't fully torn, you can bleed as it pulls away.
Otherwise, it just means you're one of the lucky ones who doesn't have to worry about the blood :)
~ Em
Not everyone bleeds the first time. The hymen is a piece of tissue inside the vaginal opening that USUALLY tears the first time someone has vaginal sex. This is where the bleeding comes from. However, it can be easily torn by tampons, masturbation, bike riding, horseback riding, and injury long before any sex occurs. Rarely the hymen doesn't break, but this usually is made obvious by extremely uncomfortable sex. If this is the case there are surgeries that can be done to remove it, although it's much more likely it was already broken.
Not an expert on hymens. Try reading wikipedia as well.
The bleeding comes from tearing blood vessels when the hymen is torn. As far as I can find out, not all women bleed the first time (according to wikipedia, a survey said less than 43% bleed). The shape of the hymen would also play it's part, if it doesnt cover much then it wont have to break.
My guess is that it probably wont bleed. It either got torn but didnt tear any blood vessels or it didnt get torn at all.
Hope this helps.