Lets do something that you've wanted to do

You close the door behind yourself locking you and Jessica inside the bathroom. You then start to strip, giving your sister a naked view of your body. As you strip, you also sent a message to her telling her that "we're family, so why not take a shower together?" Once done, Jessica asks you to join her in the showering.

"Definitely," You say. So there you are, you're both standing face to face inside the shower with the door closed. The shower is small, but still can fit 2 people inside with barely enough room to be able to turn around.

You tell Jessica that you can help her wash her back. Her body trembles a bit, but she says "yes" with a little bit of redness in her face. By her expression, you know that you might be the first one to take your own sister's cherry. The feeling of an incestious relationship, has turned you on once again. Your cock is now fully erect as you trying to wash Jessica's body. The smoothness of her skin and the bouncey feeling of your meat, makes your cock even larger. Now your cock is pushing against Jessica's ass. You feel like you can't take it anymore. You hugged Jessica, with both your hands over her body, grabbed those firm tits with a little squeese. Jessica started struggle a bit,

"What are you doing? No! Get off! Ah!" Jessica says quietly as she doesn't want your mom to hear it in the kitchen. She can feel your cock is erect and already tunneled between her leg with your cock fat head pressing against her pussy. The situation also turned her on since what you're thinking is also affecting her in a way.

Now, what should you do? do some more caressing or fuck her right away?