I just got my kitten from someone and now that she's (i think it's a girl) here, She keeps hiding. She will come out and play but will hide more then not. Is this bad???
First, you have just brought her home, so think about her situation from her perspective. There she was, in a home that she was used to, likely with her siblings and mother, and likely the only place she's ever known in her young life. Suddenly, someone she doesn't know comes and takes her away from her home and family, putting her in a place she's never seen before, with all kinds of strange sights, sounds, and smells. It's really not surprising that the first few days that a kitten or puppy comes to a new home they are somewhat quiet and withdrawn. It takes them a while to get adjusted to their new surroundings, and that's perfectly normal. Give her some time and she'll start coming out of her shell. Make sure she is eating, drinking, using the litterbox normally, and growing normally. If these things aren't happening, make sure to have a veterinarian check her out.
Cats are also very nocturnal by nature, and so tend to be more active at night than during the day. This is a big reason why so many cat owners get annoyed when the cat decides that it's play time while the people are sleeping. Your kitten will make some adjustments and get used to your schedule, but will always have some activity during the night. You may be trying to interact with her when she thinks it's nap time. Cats also like enclosed places when they're nervous, so hiding to sleep or simply wait is very normal.
If you have any concerns about her, make sure to take her to a vet. You'll want to go ahead and plan on this soon anyway, as it's important to have her tested for intestinal parasites, feline leukemia, and feline AIDS, and make sure she receives her first vaccines on time. Have fun with the new kitten! And when she is having a "kitty spaz" around the house at 10:30 at night and literally bouncing from the walls, think back to when she was nice and quiet. :)