My daughter having sex ...

My 16 yr old daughter claims to be “straight” as she doesn’t feel emotionally for girls. But, one day i️ walked in on her going down on a girl! We talked about it and she said it just feels good. How do i️ react? Is this bad ? Positive ? Gross ? I’m just confused. I️ know she’s not a virgin either she’s had three sexual partners but it wasn’t ever under my roof. or at least when i️ was home because she always had to keep the door open. i’m supposed to make ber keep her door open with girls now ? i️ am open to all sexualities she’s just 16 and i’m confused