Is it immature to want an attractive partner?

I was discussing preferences with someone that was much older than me, and I told him that personality and looks were equally important to me, and that I couldn’t date someone that had a great personality but wasn’t especially that good-looking. He responded with “Yes, but that’s because you’re still young. You’re only 21. You’ll care less about looks when you grow up”.

And while I thought it was a bit condescending, this lead me to wonder if wanting a good looking partner was a sign of emotional immaturity?