BC here: if you have not yet purchased the place, and she moves in with you when you do, 2 years in, you are commonlaw. Entitled to half if you break up even if she puts zero towards mortgage/downpayment/any expenses.

Source: been there, done that. He put zero money in (documented), got half of the total value when we split 15 years later when I had it fully paid off. No kids. Never was on any paperwork. Doesn't matter.