My Kitten is like 4-6 weeks old. She is roughly the size of my hand. I was wondering if she will be small when she grows up or is this normal for kittens
There is a section on the forum called "Pregnant Cats and Kittens." There is a huge amount of information there, and the experts can help you with any specific problems you're having with your kitten.
And, of course, we'd like to see photos of your kitten, too! A lot of times, that can help us know what to tell you.
Your kitten is very young. Younger than is the common for adopting/buying kittens.
So you can essentially see her as an orphan.
There is a good site for rescuing orphans, www.kitten-rescue.com
Look at it, it should give you lots of ideas.
Try to get a couple of good cat books in your library. There are also some thema articles in our overall site, www.thecatsite.com. Look also there... (in fact, you see some already here being in the Forum, just look above the Forums to the right - feks "Cat Care"
Please describe more about what you are doing, and how does she have - it will be easier to fill in with advices...
Is she eating on her own? Is she pooing and peeing on her own? (use NON clumping cat litter, not parfumed.)
How is her overall health? How did you get here?
Good luck!
ps. About your question: what it will be with a miniature kitten.
It is not clear yet what she is, as she may be as you say, 4-5 weeks, and perhaps somewhat undernourished.
But miniature cats does happen. You see it if you can compare with their siblings from the same litter. Some makes it into adults and may live long lives. Some does not live so long. Going down before they get adult. Only to do is to make sure they get a good life, and hope for the best.