Is it OK to think my new stepbrother is good looking?

I'm a 17 year old girl and my new 14 year old stepbrother has been living with us for a few months and we are getting along great. The only problem is I can't help but notice he has an adorable babyface and is a really good looking kid. Since we didn't grow up together and we aren't blood related, is it OK to think my stepbrother is very cute?