I am thinking about breaking up my 3 year relationship

I love my girlfriend very much, I want to start there because I hate that I am thinking about this. The situation is that she recently graduated college (I still have one year left) and as any long term couple we have been thinking about living together for a while. The plan was to start saving, and then build a house in a field that her parents gave to her, like an advance inheritance, the field is under her name and everything, I used to be ok with this, it sounded great but then I found out where this field is.

And it is just next to her parents house, like 8 steps away of her parents house, live living in their backyard. She didn't told me this, she casually mention it one day and I got genuinely scared, her family is very controlling and even though they have been nice to me, and I am nice to them, we are just people that don't get along very well, my personality just doesn't fit with their way of living and sometimes we have disagreements.

So this whole situation seems like a terrible idea to me, the only thought of me living there makes me so anxious, and of course we talked about this, I offer some alternatives, but she said that this was a non negotiable, she wants to build her house there, which at the end I understand, because that's her land. But on the other side it bugs me a little that she is fine with living so near of her parents, she fights very often with them, and in every fight she ends up crying on the phone with me, so I didn't expect for her to turn down all of my alternatives, but I guess that for her, her plan is the fastest way to be independent. In that conversation she was also very understanding of my point of view, she told me that she doesn't want to force anything on me, and asked me if I thought that it will be a good idea breaking up, but I was so vulnerable at that point of the conversation, I couldn't stop crying, so I answered "no" and the she promised me that if I am willing to live with her in that house for some years, she will do everything in her power to buy a place away from there.

And I accepted that promise, this happened two weeks ago, and I can't stop thinking about it. I don't want to live there, I genuinely don't, the more I think about it the more unhappy I am. It has been my dream to live with her since I met her, but now I can only imagine myself being anxious living in a place I don't belong, sharing with people that I don't get along with, just waiting for a promise that I don't even have the certainty that it can be fullfil because the house market is shit.

I have been thinking about breaking up with her when the construction of her house is already a solid plan, because right now is something in the air. And I love her, I don't want to leave her, I want all the time I can have with her before this starts, I hate this and myself for not being strong enough and just move in with her and her parents, it would be so much easier, but I will hate myself more if I force myself into that life.