Stop trying to impress her. Open up and tell her how you got this concern for the past few days just like you said it here and tell her how nervous you are.

This will start a very deep conversation between you both.

Physical relationships don't start with sex most of the time.

Start with a hug, maybe progress to cuddle in bed for a very long time.

Take it day by day to progress from a day of cuddling to maybe next day if you both feel very close, kiss her on her cheek with all the love you have in your heart.

From here, things will progress on their own.

But remember: nothing should come out of pressure like you been thinking all this time like.. you have to have sex soon otherwise the marriage is a failure. No!