Should I wait it out?

I'm a senior in high school and I've been depressed for two years now. Recently, it's gotten much worse and I want to get help, but there are a few things stopping me: I want to tell my mom about it, but she really doesn't understand mental illness and doesn't see it as a legitamite issue. I feel like she'll see me as a disappointment, or even blame herself for making me screwed up even though it's not her fault. I know therapy is expensive and I really don't want to be any kind of burden. I have three younger sisters who look up to me and I don't want them to have to see their older sister getting tangled in depression meds and counseling. I'm going to college in the fall, so part of me just wants to try and wait it out to see if a change in scenery will clear things up. I'm worried too though if while I'm there the depression won't go away and I won't be able to do well. Any suggestions would be greatly appreciated :)