Is she friendly the rest of the time?
What does she do if you pick her up when she's "attacking" your feet?
she is friendly most of the time and when i pick her up she keeps biting
It is most likely that your kitten is simply playing too roughly. Your moving feet are activating her instinct to hunt. She may just outgrow this, but it would best if we could get it under control. Make sure she has plenty of toys to keep her busy. If she gets bored with them rotate them so that she had different ones every few days. Ignoring the behavior usually works the best, XXXXX XXXXX know that can be difficult. Here are a couple other options for you. When she goes after your feet try making a loud noise. A jar filled with pennies (or anything that will shake loudly) kept close at hand is useful. Shake it, or throw it when she is about to bite or scratch to distract her. This works better than you yelling or spraying with water. Another option would be to pick her up and put her in "time out" when she does this. Put her in a room or large pet crate, and let her out after a few minutes of being calm. Whatever you do, don't yell and act excited as this will just make her more agitated as well. Here is a link to a page about play aggression in cats:
If you have further questions let me know. If this answers your question please click accept. Thank you and best wishes.