Inlaws complain that I take too long

I take 15 minutes In the shower (I time myself) and my in-laws bang on the door that I’m taking too long. Is 15 minutes too long? I ask if anyone needs the bathroom before I go and shower so I don’t understand what the rush is

I live with them but I pay my portion of bills sooo.. we live together ? 😅 In total I spend 20 minutes in the bathroom