Will my babies hair stay curly?

My daughter is almost one and has beautiful curls. Her hair is still pretty short, but it’s beautiful and I’m hoping it stays this way.

It’s funny because I have curly hair and I hate it, and I was hoping she would have straight hair, but it’s such a nice curl and I love it. I kind of figured it would stay curly since both my husband and I have curly hair, (my son also)but my sister in law is telling me that once I cut her hair, she will lose her curl- That’s what happened to her daughter.

I have no plans of cutting her hair, but obviously I will eventually.

Is this true?? Will she lose her curl?? When will I know if she will have curly or straight hair?