My brother wants to have shower...

I (F19) have a brother (M21) and we were always so close. We grew up together and did most of the things together. Now that I am a bit older and my tits are growing, he still wants for us to have shower together. When we were younger, he always plays my tits and I was okay with it. Now, I don't know if I still should... but it's still tempting.