I think another approach is to talk to your school counsellor. They ought to be a great mediator between yourself and your parents. They will be able to provide resources.

Perhaps your parents are concerned about the level of time and their own commitment in homeschooling (where the parent provides direction, creates lesson plans, and facilitates the teaching).

Another option - which considering your age is very viable - is to complete your studies by CORRESPONDENCE. Many school boards havae a distance eduacation program. If not, your state education ministry should. Correspondence allows you to be more in control of your own education when it comes to the pace of learning. But, by you being responsible for your own education - and essentially facilitating it yourself - the commitment of your parents is significantly reduced.