Is It Difficult To Have Sex If The Upper Skin Of Penis Tip Does Not Retract?

My question is about sexual problem. I am going to marry my glfriend after some days.One of my friend said me that my upper skin is not going down ,so I can not able to enter my penis into my wife,s vagina while doing sex.Is it correct that my fore skin should go down? Can you please suggest me please? Another thing he said that I must meet an operation in near future for doing sex?