Replying to College and Parents

So I have two older siblings, brother and sister, that are very smart and both went to great colleges (middlebury and bates respectively).
Now I am ending my junior year in high school and am starting to look at colleges. Im not very smart and don't take challenging courses. I try very hard in the regular classes and do decently but not nearly as well as my brother and sister. They also were extremely bright and didnt have to put any effort in throughout high school but managed to get into all great schools.
Unfortuantely my parents dont understand my situation. All they do is indirectly compare me to my bro and sis. They tell me that if I don't do better, they won't send me to a college of my choice if its very expensive. My hopefuly choices are schools like providence, uconn, uvm and such and i can probably get into those but to my parents its not enough.
Now what really pisses me off is what happened today. I tell my parents taht I got a 70 on a math test that i studied really hard for and met with my tutor twice for the test. my mom flipped out and said that ill be going to Eastern or central connecticut if im lucky...if you dont know these schools -- they are very easy schools to get into (1000 Sat) and are not what i am looking for at all. They say that its not worth their money to send me to the schools that I want to get into and that if theya re going to spend the money, they want me to go to prestigious liberal art schools and such. I understand that its their money, but they shouldnt not let me go where i want to when my sis and bro tried just as hard as me and got to go whereever they pleased. is it just me, or are my parents being extremely unfair?