Problem during intercourse. Happy!

Hello doctor, I am a 24 year old male. My height is 6 and I weigh 90kg. I got married in January 2017. My wife is 2 years younger than me. She comes from a very simple family and she has had no relationship before marriage. I am the first guy in her life. She is also the first woman in my life and both of us have never had physical relationship ever before. Now since april 2017, we are trying to have intercourse but unable to.My wife is very shy and does not know much about sex. I masturbate every day in the night before bath on my bed. I stopped masturbation after marriage and am unable to have sex with my wife. Also my wife is very sensitive when I touch her vagina. she resists a lot if I do it with two fingers. I wonder how I will ever penetrate her with such small space. Also we tried penetration a lot of times but the moment I come close to her I lose erection. We are very frustrated. I am very uncomfortable with my foreskin rolled . Please help us. we want to be sexually happy