Related to virginity of my wife. Doctor?

Sorry doctor I am asking this question, In October I am going to complete one year of my marriage,from my wife I asked about her virginity and she told clearly that she is virgin, I saw her vagina during our first sex, Which almost took an hour to insert my penis into her, It was painful for her, and I took a look at her vagina but I was unable to see hymen, Also I don't know how to see it, After one week of our sexual life I looked her vagina thoroughly and found that hole was considerably big compared to that pics of Virgin vagina's I see in internet,  I am unable to understand it, I am a professor but this thing becomes an anxiety for me, age of my wife is 33 , can there is a difference in size between virgin vagina of a 18 year and 30+ old girl, I mean that can vaginal hole size differs, please help me doctor regarding this, I want to live a happy life..