My girlfriend of 4 months and I were showering together. I told her that she had an aesthetically pleasing vagina - solid 9/10.

She told me that that was a backhanded compliment asked whose vagina would get a 10 if hers did not. I told her that nobody would, I just said 9/10 because she wouldn’t believe me if I said a 10/10 (she’d do that thing where she just said no that’s not true you’re just being nice because you’re my boyfriend). My girlfriend is upset.

What can I say to make her feel better? Am I the asshole here or is she too sensitive?

EDIT: After consulting the great people of Reddit, I am going to declare myself a dumbass, but not an asshole. Pray for me boys.