I want to ask to reduce the amount of time my step daughter stays with us
Why do you want to reduce the amount of time your step daughter stays with you?
Because I feel that it is disrupting my life.
Family is important, but It's okay to want your space. Try to be as accommodating as possible and explain your reasoning to them. They may feel a little hurt or possibly understand completely.
I was going to say she was just too damn annoying. Every time she comes over she begs us for money.
I completely understand how annoying that could be. It's wrong for someone to not only stay at your place but beg for money. Especially if she's an adult, she should know better.