Hmm, dear, I think you may be a wee bit caught up in whose fault it is. :)
When you say "I don't take control very easily," what do you mean? Is you lower leg secure, and in the right place? Are you using your seat? Are you giving clear, correct aids?
More likely than not, she's fine. Riding horses is about communication, to put it pretty simply. That's why it's so important to take lessons, and ride correctly. You're just learning to communicate, if we take it to a very basic level. It's complicated, but more likely than not, you're having trouble communicating with her. Maybe you're not using enough leg. Maybe you're not secure enough in your seat yet for her to respect you.
It's where we all start; every single one of us has had trouble "controlling" a horse countless times, without exception. And more often than not, that trouble is entirely our fault. ;)
There's nothing wrong with that, but just remember not to get too frustrated. Focus on your own riding, and make sure that you're doing everything right before you immediately resort to being exasperated with your horse, no matter which it may be. I know that it can be difficult, but life is.
The hills were bathed in moonlight, the shadows not so stark;
Silver light reflected off his brown hide as he held me in the dark
I love you, Mudpie!