I'm going to have concensual sex with my girlfriend
what's on your mind ?
I just thought it would be nice.
It's good that you don't take your gf for granted. Even though she's your partner sex has to be consensual.
But she doesn't have to be in the mood?
She absolutely does need to be in the mood, or willing to consent in order to please you even if she isn't.  If she says no, you need to respect that regardless of your own wishes!