My girlfriend (25f) and I (25m) bought my grandparents house at the start of the year. My grandparents wanted to downsize and when they told us this, we told them we'd love to buy it from them (started this process last year) and they agreed. They also gave us a really amazing bargain because they wanted to help us with our forever home. I was so happy because it's the house I really considered home as a kid and it still felt that way to me.

For some background to explain it. My parents had me younger since they were 19 and 21 and it meant my grandparents really had to step up to help with me. Even though my parents technically raised me and I technically lived with them, I spent FAR more time with my grandparents. I was at their house Monday through Friday before and after school and from 6am to 8pm every summer. There were times I spent a week or two at their house while my parents were especially busy or if they wanted to vacation without me.

My parents settled more and started having more kids when I was 11 and I was pressured to spend more time with them and at home so I'd bond with my siblings. This meant I didn't spend as much time with my grandparents at their house. But it never stopped being the place I felt was home. I'd even say my grandparents were more parents than my actual parents were when I was a kid.

So my girlfriend and I bought this house together and we told our families after it was official. My parents took offense to me calling it my childhood home. They said I grew up living with them and was raised in their home. My grandparents reminded them I spent more time in their (now mine and girlfriend's) house than my parents house. That wasn't good enough for my parents. They said it was insensitive and was a dig at them. And I said that wasn't what this was. I told them it as about what felt true to me.

My parents said it was disrespectful to them and I wouldn't change their mind. That I should have known better. AITA?