Do you think it's wrong if I tell my girlfriend that I don't want her to see her friends?
It sounds a little harsh. Why don't you want her to see her friends?
She spends too much time with them and not enough time with me.
She should be allowed to see her friends. Spend time with your own friends too, that will help settle your jealousy. You shouldn't try to control the people your girlfriend spends time with.
I think she should stop spending so much time with them.
You have to understand that we all need to spend time with our friends. Your girlfriend will still have plenty of time for you. You should relax and trust her.