Well, you said yourself she is being reasonable, and since you think she is, you'd better listen to her. I don't know what other option you have, since you are not self-supporting yet.
Why don't you have her lay out some *specific* goals you must reach in order to have a boyfriend, such as an exact age, and what kind of grades, etc. This will give you an idea of whether or not she is being unreasonable. If good grades to her means she wants you to get all Cs, for example, I don't think that is ridiculous.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?