Is it rude to reply that way?

So I have a 2 y/o daughter & a 6 month old son. There’s been a couple times where someone will say “you’re daughter is so beautiful” & without thinking I just said “I know, isn’t she?” & then I realized that probably sounded kinda conceited but the 2 people I’ve done it to (1 stranger, 1 family friend) didn’t act/look offended (which doesn’t really mean anything but yeah).

Anyway today when I was with my mom her friend said “you have such beautiful children” & I wasn’t *really* paying attention as I was talking to someone else & I just said, “I do. Thank you!”

My mom told me after I got my kids in their car seats getting ready to leave that my response was rude & I should’ve just told her thank you for the compliment.

But like... is acknowledging the fact that I agree that I think my children/family are beautiful/cute rude??