OP - please tell me that you are making comparisons based on 4 year costs - and not just the first year x 4. For example, you are making adjustments for changes in family size (if older siblings graduate, etc). I am kind of surprised that based on your family income, Williams is not giving you more aid - they were very very generous to my pups, even though they ultimately decided against Williams in favor of Columbia and Stanford. The Williams FA office was SUPER helpful to us - they helped us figure out the 4 year costs of all the schools on our lists. From my perspective, it does not make sense to me that they would have the same net cost for 4 years as Bowdoin/Carleton (also great schools, but I thought they included more loans in their aid package).
My D was very close to going to Williams - she really loved it there, and there was no question that it would be worth attending for the net price / aid package they had offered us. While I remain delighted that she ended up at the right pick for her, it is still very far away from home, so I selfishly would also have been very happy had she attended Williams. If your parents are helping pay, have you asked them about their thoughts? Just the fact that you want to share your decision-making process with them may be more helpful to them - and to you - than you might think.
Talking with them in a “Hey, this whole thing is maddening and its only my whole entire future at stake, so you taught me since before kindergarten that to make good decisions, I first need to get good information, so here’s what I found so far…Am I missing something?”
Last, I just wanted to congratulate you on having such great choices - you are a great student and you have a great future ahead of you. I am sure you will make the right choice for your own situation.
Best of luck!