We raised two kids and many pets in a 1200 sq ft home. The only time it was difficult was when our oldest was a high schooler, and he hogged the one and only bathroom. Now he's in college, and when he comes home, he's gotten better about not monopolizing the bathroom. We still have our second kid living at home. During the pandemic, I fostered pregnant dogs and their litters of puppies, so at one point we had 13 dogs in 1200 sq ft - but most of them puppies. Now we only have 4 pets.
So... maybe consider adding another bathroom
We're the exception for the US, but I've lived in Paris and Tokyo, where families live in very small spaces. Don't feel too bad, OP, and enjoy not having a huge mortgage. We're going to be mortgage-free in June!!!